75 504GL Over Heating
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  1. #1
    1000+ Posts Shobbz's Avatar
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    75 504GL Over Heating

    I know that i must sound like a hypochondriac, but tis true, the problems are real.

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    Today, admittedly it was a very hot day today; the pug almost hit the red on the temperature gauge. It started to ping in normal driving, I assume because of the heat.

    Recently it is guzzling fuel? Is it evaporating due to heat? Seems unlikely, but where is it going?

    Recently, new radiator, thermostat, Fan working, Pipes okay.

    Heating problem before the above radiator and thermostat installed.

    Could the water pump be on its last legs, bout 8 years Old?

    Timing is almost spot on, about 56deg as checked yesterday. Could the heat be throwing out the timing? I thought that it worked the other way around

    thanks

    James
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  2. #2
    Gone Fishin' Ray Bell's Avatar
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    Turn on the heater... that takes some heat out...

    Guzzling fuel? Well, it burns best when it's evaporated, that shouldn't be the problem... check carefully for leaks in the line? I mean when it's hot and running...

  3. #3
    Gone Fishin' Ray Bell's Avatar
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    Oh, how about this one?

    Did you flush the block out when you put that radiator in? You could well have set it up to accept a lot of flaked rust that was lying around inside...

    While it's still freshly floated into the tubes, take the radiator out and give it a good reverse flush. And flush the block... hose in the top radiator outlet from the water pump, leave it run, also take out the plug at the bottom of the block.

  4. #4
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    classic 504 overheat fault is the welsh plug in the front of the head has corroded and fallen out,it sits against the water pump impellor and grinds the fins away,sometimes no noise at all.seen this many times.i normally start with rad and stat with block flush as ray said,check if you thermo fan is cutting in or it may be locked on.check gas leakage from head gasket etc.then tune items,if tune was out that bad to overheat it would not run very good anyway.is the car actually overheating or is it just the gauge ? what temp stat you running.what coolant.

  5. #5
    1000+ Posts Rod Hagen's Avatar
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    Your not having much luck, James!

    Firstly, you say "Timing is almost spot on, about 56deg as checked yesterday" . Just to be clear, that's actually the points "dwell angle", not the "timing". The normal timing on a 504, from memory (so check it) , is about 8degrees advance. If the timing is out then it may explain overheating (and perhaps the fuel consumption).

    That said, its probably something else.

    The worst possibility first:

    "Using lots of fuel and overheating" can be a symptom of something nasty like a burnt out exhaust valve. A compresion test is probably the easiest way to make sure that you don;t have some sort of "major" problem like this underlying your other issues.

    Another, uncommon but possible, thing that can cause these symptoms is an exhaust blockage (happened to me on a 505 once).

    If the overheating and fuel consumption issues aren't directly related to each other then a range of other possibilities pop up.

    A deteriorating water pump could be the problem if the problem which charles mentions is occuring. I haven't seen this particular one myself, but it makes some sense.

    A simple, quite common, problem causing overheating though is deterioration of the upper (EDIT- whoops, make that LOWER - thanks Ray) radiator hose. Were the hoses replaced when you put in the new radiator? The hoses disintegrate internally and "collapse" from the vauum created by the waterpump. They can look perfect on the outside.

    I seem to remember that your car is an auto. The radiator also acts as a transmission fluid cooler. If the transmission is running "hot" because of low fluid levels or deteriorated transmission fluid, or other issues like slippage, then this can cause engine overheating. THis might also be related to high fuel consumption.

    When exactly does the "overheating" occur? When idling at the lights after a bit of a drive, or when driving at reasonable speed? If its the former then I'd tend to suspect a pump / circulation / fan problem.

    A couple of weird ones:
    Does the engine actually seem "hot"? One quirky issue can involve a problem with the voltage stabiliser (a little unit that plugs in behind the dash board). If this goes , then the temperature gauge reading can actually vary with things like engien revs and the use of other power circuits.

    Secondly is the battery charging at its normal rate. If the voltage regulator (a different thing, mounted on the firewall in the engine bay) is defective, or its leads come loose, then the charging system can be pumping out far more than it should be (ultimately killing your alternator and battery!) This can also lead to faulty tempertaure readings.

    Another thing that can cause the problem is binding rear brakes. I seem to remember you were having some rear caliper problems?

    The most common cause of overheating issues, though, is poor circulation, either because of blockages in the cooling system or the water passages of the engine itself, or because of poor water pump performance.

    Cheers

    Rod

    <small>[ 11 September 2003, 01:02 PM: Message edited by: Rod Hagen ]</small>
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  6. #6
    Fellow Frogger! frogs4ever's Avatar
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    Rod Hagen:
    Your not having much luck, James!

    The normal timing on a 504, from memory (so check it) , is about 8degrees advance.
    Rod
    According to my Haynes manual, the correct timing for the GL (carby XN1) is 5 degrees BTDC with the vacuum advance disconnected. Retarded timing will contribute to engine overheating, but so will excessively advanced timing as the resulting pre-detonation/pinking will cause combustion chamber temperatures to soar. But regardless of whether you timing is advanced or retarded, pinking will occur if the engine gets very hot.

    Others here have posted plenty of good suggestions worth following up Shobbz. But here is one more common problem which has not been mentioned. You should double check that the the fan is working properly, as this can be very deceptive at first glance. Here's why. When the engine is running, the radiatior fan on a 504 will always 'appear' to be working, when in fact it is just free-wheeling. When the radiator gets up to a certain temperature (about 80 degrees I think) a thermostatic switch in the bottom of the radiator sends power to a carbon brush which rubs on the water pump pulley assembly. This in turn sends current through an electromagnet which engages a clutch on the fan pulley. At that moment you will here a 'click' or 'clunk' and the fan speed will dramatically increase above its normal lazy freewheeling speed. All of what I've just described is assuming that everything is working properly. Common faults in this system are:
    Carbon brush worn down so it is either not touching the pully at all or not touching firmly enough to give a good current flow;
    Fan clutch clearance too wide - in need of adjusting, thus causing fan slippage, especially at high engine temperatures when further heating of the components causes the gap to widen a little more;
    The thermostatic switch and condition of the wiring may also need to be checked. It is also worth noting that the power to this system runs through the same fuse as the brake light circuit. So check to see if your brake lights are working!

    Anyway Shobbz good luck - I hope you get to drive and enjoy you car soon - you seem to be having an awful lot of problems. Was your 504 badly neglected by its previous owner?
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  7. #7
    1000+ Posts Rod Hagen's Avatar
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    frogs4ever:
    According to my Haynes manual, the correct timing for the GL (carby XN1) is 5 degrees BTDC with the vacuum advance disconnected.
    Mmm. Says 8 degrees in the 504 drivers handbook that I just found lying on the shelf. From memory the Aussie emission control cars had a different set of specs from the ones in Haynes. I could be wrong though. Used to be on a sticker under the bonnet telling all!

    I agree about the fan. It certainly is deceptive if you aren't familiar with it. The best way to check is to simply watch the thing heat up and wait for the "clunk" and changed engine sound!

    Cheers

    Rod

    <small>[ 11 September 2003, 10:35 AM: Message edited by: Rod Hagen ]</small>
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  8. #8
    Guru davemcbean's Avatar
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    Another thing worth noting is that the 504 temp gauge is coloured in a little pessimistically.

    The beginning of the red zone just means "keep an eye on things". You don't have to stop driving until they get halfway into the red zone.

    The series 1 505 gauge is worse. The red zone only starts at the very end of the gauge. By the time the needle hits the red zone they've well and truely overheated. From about 1982 onwards they fitted a warning light which comes on from about the middle of the gauge onwards, to let you know to keep an eye on things. They also have a "stop!!" light which comes on before the gauge gets into the top third of its range. I wouldn't let a 505 get into the top third of the gauge, regardless of whether the stop light comes on or not, even though this isn't in the red.

    Keep in mind that there will be a slight variance from gauge to gauge between 504s, although in my experience this variance is nothing like as large as that which you get with 504 fuel gauges.

    Dave
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  9. #9
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    If you just fitted a new radiator you may want to bleed the cooling system of any air. The presents of big air bubbles can cause it to over heat.

  10. #10
    Gone Fishin' Ray Bell's Avatar
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    That would be the bottom hose collapsing, Rod...

  11. #11
    Fellow Frogger! frogs4ever's Avatar
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    Rod Hagen
    Mmm. Says 8 degrees in the 504 drivers handbook that I just found lying on the shelf. From memory the Aussie emission control cars had a different set of specs from the ones in Haynes. I could be wrong though. Used to be on a sticker under the bonnet telling all!
    Rod[/QB]
    H'mm that's interesting. I don't have an owner's manual to refer to, so I have to rely on Haynes. Here's what the Haynes manual says word for word:

    504 US 1971 Standard ............................. 0 TDC
    XN1, XN2 (11CV), 504 US - 1970, 72, 73 Standard .. 5 BTDC
    XM7 (10CV), 504 US - 1969 Standard ............... 10 BTDC

    It does also mention that this is subject to alteration by manufacturer, check handbook or local dealer!

    By the way Shobbz, your 504 should have the XN1 motor.

    In practise, I find that my 504 pings at anything above 5 degrees BTDC. But that may be because I'm running 96 RON Premium Unleaded, which is the highest available in Tassie, when the car was by most accounts intended to use 98 RON leaded.

    When I had a new Ducellier dizzy fitted by my local French car workshop last year, he set it to 5 degrees BTDC. I didn't think to ask him why, or what the factory setting is supposed to be.
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  12. #12
    1000+ Posts Rod Hagen's Avatar
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    This particular handbook with 8 degrees is for an early XN1 equipped Australian asssembled car, frogs4ever. I'm pretty sure our own later 1978 504 auto GL was 8 degrees too. Can't find the Autobook 504 manual to see what it had to say on the matter I'm afraid. The XN1's in 505's were usually 8 or 10 (with 10 in the XN1A).

    Dave should know! Dave???????

    Cheers

    Rod
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  13. #13
    Guru davemcbean's Avatar
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    Rod Hagen:
    The XN1's in 505's were usually 8 or 10 (with 10 in the XN1A).

    Dave should know! Dave???????

    Cheers

    Rod
    Yeah, the Euro 505 two litre cars ran 8 and 10 degrees as Rod said.

    Many 504 engines can handle 10 degrees with good fuel, but with crap fuel and partially blocked jets will struggle to take more than 5 degrees without pinging.

    What distributor you're using has a bit to do with it. M48 dissies have a slower rate of initial advance than some of the others, so they can generally take 8-10 degrees of idle advance.

    Most engines should be able to take 6-8 degrees. Often the front pulley is a little loose on the keyway and flaost around by a couple of degrees, so I just set them where the pulley is floating in the 6-8 degree range. If they then ping I retard them a couple of degrees. If not, I leave them.

    Dave

    <small>[ 11 September 2003, 12:57 PM: Message edited by: davemcbean ]</small>
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  14. #14
    1000+ Posts Rod Hagen's Avatar
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    Ray Bell:
    That would be the bottom hose collapsing, Rod...
    Yes, that makes much more sense, Ray. Thanks. Sorry if you've been frantically undoing the wrong hose clamp James! dead

    Cheers

    Rod

    <small>[ 11 September 2003, 01:05 PM: Message edited by: Rod Hagen ]</small>
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    Fellow Frogger! frogs4ever's Avatar
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    Rod Hagen:
    This particular handbook with 8 degrees is for an early XN1 equipped Australian asssembled car, frogs4ever. I'm pretty sure our own later 1978 504 auto GL was 8 degrees too. Can't find the Autobook 504 manual to see what it had to say on the matter I'm afraid. The XN1's in 505's were usually 8 or 10 (with 10 in the XN1A).

    Dave should know! Dave???????

    Cheers

    Rod
    How early? I think the first 504's had an 1800cc motor. As I understand, the two litre unit was introduced a year or two later. I could be wrong though.

    But regardless of what the books say, in practice I cannot run mine above 5 degrees BTDC due to the nasty pinking that results. I would be interested to hear other 504GL owners experiences in this regard.

    My 504 is very touchy about ignition timing. Slightly too advanced and in pinks like crazy. Slightly insufficient advance and it becomes gutless and guzzles fuel. My old Renault 16TS used to go like a cat on a hot tin roof in just about any state of tune. Renault make great engines.

    Cheers,

    Doug.
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  16. #16
    Fellow Frogger! frogs4ever's Avatar
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    Originally posted by Rod Hagen:
    I agree about the fan. It certainly is deceptive if you aren't familiar with it. The best way to check is to simply watch the thing heat up and wait for the "clunk" and changed engine sound!

    Cheers

    Rod
    Yep. Shobbz, the fan should kick in as Rod describes after about 10 minutes of idling from a cold start or about 2 to 5 minutes idling when warm. In my experience the fan kicks in when the temperature guage reaches about 1 mm below the red zone, then disengages when the temperature guage gets down to about half way. When the fan is engaged the sound from the engine will be a fairly vocal roar as the revs rise, and there will be a noticeable loss of power as the fan saps quite a significant percentage of the engine's power. This loss of power, however, must not be confused with the loss of power that you will notice when the engine is about to seize to due to severe overheating .... god forbid. mallet

    <small>[ 11 September 2003, 01:25 PM: Message edited by: frogs4ever ]</small>
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  17. #17
    1000+ Posts Rod Hagen's Avatar
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    frogs4ever:
    How early? I think the first 504's had an 1800cc motor. As I understand, the two litre unit was introduced a year or two later. I could be wrong though.
    You are quite right about there being an 1800 first of all in 1970 & 71 in Australia , Doug, but that motor was designated XM, not XN. This handbook is from an earlyish Australian 2 litre with an XN1, 2 litre motor. I'm not certain of the particular year of the car that it came from (it belonged to a mate) , but I have a feeling it may have been a 74.

    There does seem to be a lot of varaibility in 504's and 505's in terms of their "pingability" , judging by the posts that pop up here. Our 504 was actually very tolerant, but my first 505 wagon wasn't at all. The one that followed it (with an identical motor) was far less pernickety.

    I suspect it often comes down to things like the amount of work that has been done on cylinder heads, the level of "coking", the effectiveness of advance mechanisms, the amount of dimpling and wear on push rods, camshafts and rockers, etc etc with cars that have got to this sort of age.

    Cheers

    Rod

    <small>[ 11 September 2003, 01:31 PM: Message edited by: Rod Hagen ]</small>
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  18. #18
    Fellow Frogger! frogs4ever's Avatar
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    Rod Hagen:

    There does seem to be a lot of varaibility in 504's and 505's in terms of their "pingability" , judging by the posts that pop up here. Our 504 was actually very tolerant, but my first 505 wagon wasn't at all. The one that followed it (with an identical motor) was far less pernickety.

    Cheers

    Rod
    Thankyou, that helps to put things into perspective.

    Doug.

    <small>[ 11 September 2003, 01:34 PM: Message edited by: frogs4ever ]</small>
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  19. #19
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    frogs4ever:

    But regardless of what the books say, in practice I cannot run mine above 5 degrees BTDC due to the nasty pinking that results. I would be interested to hear other 504GL owners experiences in this regard.

    My 504 is very touchy about ignition timing. Slightly too advanced and in pinks like crazy. Slightly insufficient advance and it becomes gutless and guzzles fuel. My old Renault 16TS used to go like a cat on a hot tin roof in just about any state of tune. Renault make great engines.

    Cheers,

    Doug.
    Doug,

    In my experience, many 504/505 2 litre engines are like your Renault experience, very unfussy with regards to tuning, although I have struck a couple which have been like your 504. I suspect these "fussy" cars have one of the following "problems":

    a)head shaved, resulting in over 9:1 compression, in which case they need richer jets. This is probably one of the reasons why the factory books recommend not shaving the head by more than 0.5mm. Hemispherical combustion chambers without a squish area are more prone to pinging at high compression ratios than engines with a squish area. The 16TS has a small "squish" area.

    b)Burs on the combustion chamber. When heads are shaved you must debur the edge of the combustion chamber other wise the burs will get hot and act like glow plugs resulting in pinging.

    c)partially blocked jets (which make them run a tad lean)

    d)worn distributor making it hard to get accurate timing

    e)too much "coke" build up resulting from being driven too gently. In other words never taking them over 5000rpm (personally I reckon this should be done atleast once a week, but it's just my opinion).

    Dave

    <small>[ 11 September 2003, 01:47 PM: Message edited by: davemcbean ]</small>
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  20. #20
    Budding Architect ???? pugrambo's Avatar
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    i used to run 10 degrees on my twin DCOE 504 with TI cam but with those carbies i was running a little more fuel than a standard setup
    you need to just set the car where it is happy
    i'd set mine then take it for a drive and adjust accordingly and never ever used a timing light
    it was all done by ear and the car ran like a treat
    504 engines are a dead simple thing once you have had a little bit of time spent playing with them
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    Budding Architect ???? pugrambo's Avatar
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    btw
    if you are going to flush the rad and the block grab a pair of stockings and place some over the top hose and clamp it back up when you are done and at least every couple of days pull it out and clean it then put it back
    you will suprised on how much junk you will catch in there and in doing so keeps it from going all the way back through your system
    just don't make it too lon that it gets sucked into the pump
    just cut the foot off the stocking
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  22. #22
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    davemcbean:

    Doug,

    In my experience, many 504/505 2 litre engines are like your Renault experience, very unfussy with regards to tuning, although I have struck a couple which have been like your 504. I suspect these "fussy" cars have one of the following "problems":

    a)head shaved, resulting in over 9:1 compression, in which case they need richer jets. This is probably one of the reasons why the factory books recommend not shaving the head by more than 0.5mm. Hemispherical combustion chambers without a squish area are more prone to pinging at high compression ratios than engines with a squish area. The 16TS has a small "squish" area.

    b)Burs on the combustion chamber. When heads are shaved you must debur the edge of the combustion chamber other wise the burs will get hot and act like glow plugs resulting in pinging.

    c)partially blocked jets (which make them run a tad lean)

    d)worn distributor making it hard to get accurate timing

    e)too much "coke" build up resulting from being driven too gently. In other words never taking them over 5000rpm (personally I reckon this should be done atleast once a week, but it's just my opinion).

    Dave
    Very interesting post Dave. You've enlightenned me to some issues which are new to me and worth looking in to, as well as some which I'm already familliar with.

    a) At the time of purchasing the car, about 18 months ago, I was struck by how clean the cylinder head looked compared with the rest of the motor (old and covered in gunk). So, yes, I wouldn't be surprised if the head has been off for repairs, and shaved, at some time. But judging by the (dark grey / blackish) colour of the soot in my tailpipe, I suspect the jets do not need to be any bigger in my case.

    Can you please explain what is a 'squish area'? I've never come accross that term.

    b) If the head has been shaved, I wouldn't be surprised if they have left 'burrs' like you mention above. That would help explain why she pings when the engine is quite hot.

    c) Don't think so in my case, judging by the colour of the exhaust, but worth considering.

    d) Dizzy is only a bit over 12 months old, points are in excellent condition, gap correct, mechanisms properly lubricated etc.

    e) Coke build up is quite likely thanks to previous owners (old man, then female matric student). A few days after purchasing the car, I replaced the spark plugs and was astonished by the amount of furry black carbon almost obscuring the business end of the plugs, and missing chunks of metal here and there probably due to detonation. They were a sorry sight. Since then I've replaced the plugs a couple of times and they've been fine. Also since then I've been regularly driving the living daylights out of the car. I firmly subscribe to your view that a trip over 5000 RPM at least once a week is a healthy thing. I've even got the kickdown cable adjusted fairly tight so that she goes down a gear more readily, and frequently take advantage of this for overtaking and going up hills. But how long do I need to drive like this to remove years of heavy carbon build-up?

    I probably should take the head off and do some deburring and decarbonisation, even if it's a bit of a pain. Dave, if I were to take the head off, do you think it would be worth pollishing the combustion chambers and valve heads at the same time? Would this prevent future carbon buildup?

    <small>[ 11 September 2003, 03:38 PM: Message edited by: frogs4ever ]</small>
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  23. #23
    Budding Architect ???? pugrambo's Avatar
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    a fairly good decarbon can be achieved with some redex
    i can recomend this to decarbon a car very well
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  24. #24
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    But judging by the (dark grey / blackish) colour of the soot in my tailpipe, I suspect the jets do not need to be any bigger in my case.
    I think you said you were running premium unleaded fuel in it, Doug. With unleaded you inevitably get a much "blacker" colour in your tailpipe than you would have been used to with leaded fuel, even if it is running pretty lean.

    Cheers

    Rod

    <small>[ 11 September 2003, 04:22 PM: Message edited by: Rod Hagen ]</small>
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    Fellow Frogger! frogs4ever's Avatar
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    Rod Hagen:
    I think you said you were running premium unleaded fuel in it, Doug. With unleaded you inevitably get a much "blacker" colour in your tailpipe than you would have been used to with leaded fuel, even if it is running pretty lean.

    Rod
    Looks like I've learned something else today, thanks Rod.
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