Hi fellas, the mechanic overhauled my 404 yesterday, smoke had been coming off the breather tube for quite some time and compression was bad. Now my concern is that the car is so hot, you won't feel the heat in the cabin as you drive but if you touch any part in the engine, it's boiling hot, alertnator, tappet cover etc. I don't understand what could be the problem, car was never this hot before rebuild. When I removed the head a few days before the rebuild, just as I was removing the water pump, a round piece of metal popped out(it's like a plug) like those 2 external ones on the back of the head but this one is inside the head(the water pump presses against it). The mechanic insisted we shouldn't put it back on because it's loose, he mentioned that it shouldn't have automatically popped out as I removed the water pump, it's supposed to be fixed onto the head but I'm confused because I believe I read somewhere long ago that running without that plug may cause overheating. Please tell me guys, is this the case and is that plug supposed to be fixed? I thought it was the water plug that holds it in place. Thanx.
404 cylinder head plug
- Thread starter Edmund
- Start date
Good god, don't listed to that "mechanic"!
Yes the plug has to be there and if it's popped out then the head is corroded badly and needs a lot of welding, machining and a new plug.
Yes the plug has to be there and if it's popped out then the head is corroded badly and needs a lot of welding, machining and a new plug.
That is a common problem you need a new welch plug and if coorosion is too severe for it to be peined into place a couple of very small screws may be needed.
Wuthout this plug the waterpump cannot circulate the water to the radiator so boiling engine and possible head gasket blown.
I can supply you a new plug for $10 plus post
Wuthout this plug the waterpump cannot circulate the water to the radiator so boiling engine and possible head gasket blown.
I can supply you a new plug for $10 plus post
- Joined
- Aug 2, 2000
- Messages
- 11,441
How did he overhaul your car in one day? Or did he just finish the job yesterday.
Yes it was yesterday, all done in one day(it's usually an 8 hour job)
Guys now you got me worried
find a mechanic who knows his old pugs
Actually this dude has been working on old Pugs forever, he rebuilt one for me years ago, I'm surprised at his sudden level of incompetence.
Doesn't make sense to me either. As Mike says, at the very least a new plug needs to be installed. I've been able to sometimes replace this plug without welding so it may, or not, require welding. Without that plug the water pump won't pump and circulate the water from the engine through the radiator.
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If cylinder head welding is required. A disc of aluminium can be welded in place of the pressure plug. This makes a permanent repair. I'd had this done to several cylinder heads.
That plug is absolutely critical. In the past I used 3 small stainless steel self tapping screws to hold it in as Inrobbo has indicated in a previous post.
Cooling water just wont circulate without it.
Take the pump off and try to hold the disk in using 3 small screws - refit the pump and make sure the impeller doesn't hit them when turned.
The best way, however, is head removal and weld a new plate in place.
Cheers
Roland
Cooling water just wont circulate without it.
Take the pump off and try to hold the disk in using 3 small screws - refit the pump and make sure the impeller doesn't hit them when turned.
The best way, however, is head removal and weld a new plate in place.
Cheers
Roland
- Joined
- Aug 2, 2000
- Messages
- 11,441
I drove my 404 from Adelaide with this plug rattling around. Worst trip of all time with out of balance wheels etc. Every car I have bought from interstate has had major issues. The 3 from Sydney were totally unroadworthy and NSW cars are supposed to have a RWC every year!
On the other hand I competed in a 3 day rally in a 504 with the plug loose. It was extremely hot weather and the car only overheated slightly, did better than lots of others. It was running on LPG with Gas Research equipment, don't whether this made a difference.
On the other hand I competed in a 3 day rally in a 504 with the plug loose. It was extremely hot weather and the car only overheated slightly, did better than lots of others. It was running on LPG with Gas Research equipment, don't whether this made a difference.
^ I second this.
My local Pug mechanic used to screw in a plug, and I have done it a few times too.. If you don't want to take off the head again, you will need to take out the radiator and water pump. Use stainless steel screws only....they are incredibly strong. Others will snap while you put them in. And you have to drill the holes (in the head behind the water pump) a slightly bigger diameter than if you were screwing into sheet metal or wood, as you will be screwing them into solid metal. Two of the three screws go into the metal column (which is part of the head) through which the front head bolt goes. Choose carefully the place for the third one.