V8 - cracked head?

Hi all

Recently replaced head gaskets on our 1989 3.5 EFi which was steaming like the Queen Mary and losing water like no tomorrow. Water loss is now negligible but I am still having a few problems:

When the engine is started from cold it is a bit 'clunky' under load - feels like a misfire sort of thing - and there is a bit of steam from the exhaust (sometimes a fair bit to be honest) after about 60 seconds of driving the steam goes away and the engine runs smoothly - whether the two are connected I do not know.

I asked about this prior to doing the head gaskets as I felt it was a separate problem - as a result of that I have already replaced plugs, leads, dizzy cap and rotor arm, capacitor, amplifier was new in August as was the coil. I can find no vacuum leaks or loose connections in the LPG system.

It does this whether on LPG or petrol.

The heads were not skimmed (oops) but I did check them with a straight edge and light/feeler gauges.

Frankly I'm not bothered too much about a lumpy start that clears itself but what I am wondering is whether I have a crack in the head (or a warp or something) that, when cold, allows some coolant into a cylinder, once the engine starts to warm something expands and seals the hole/crack/whatever?

Any ideas/suggestions??

Graeme

Reply to
Graeme
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Graeme, I think one thing you should bear in mind these cold, damp mornings is the amount of cold metal from the manifolds out to back that are being warmed up and causing steam, my V8 is similar in the mornings with no unusual loss of coolant.Keep checking though? Ken.

Reply to
Ken Harmes

Depending on how much moisture is coming out the exhaust it could be just condensation burning off or coolant leaking into the cylinders. Condensation is not a problem, leaking coolant is. Keep a close eye on the coolant level. If it is a leak the level will go down, probably very slowly at first then much faster as the problem gets worse. Check for oil in the coolant or coolant in the oil. If either of these occur you have a leak into the engine. I doubt that the problem is electrical or LPG.

Because of the earlier blown head gasket, the amount of steam (a fair bit), and the rough running when cold, I would suspect coolant is leaking into the cylinders. Did the engine ever seriously over heat? If so I'd consider a warped head or two. It's easy to miss if you just used a straight edge to check them. It is also possible that you have a crack in one or both of the heads. The crack may be so small that you cannot see it with the naked eye. It is also possible that the escaping compression caused by the blown head gasket scored the block between two or more cylinders (hope this isn't the case). When you checked the heads did you check the block too?

If you notice that the coolant level is dropping or coolant in the oil, etc., take the car to a good mechanic, tell him/her what you suspect and have them check it out thoroughly. If it is a problem with the heads, they can be replaced. If it is a problem with the block, you're in trouble. It may be that the heads will have to be removed to find the specific problem.

I just re-read your post . . . looks like you are still losing coolant. I hate to say this but I think there was something wrong with the engine which caused the gaskets to fail in the first place. This wasn't fixed when you replaced the gaskets. The basic problem is still there (warped heads, cracked heads, or scored block) and you will soon be leaking coolant into the engine like before. The problem will start off small and correct itself as the motor warms up, but eventually it will be so bad that warming the motor won't help.

H> Hi all

Reply to
Jim H

Hi Jim

Thanks for all of the below - current situation is that the engine no longer steams at all and the coolant level is steady - I wonder if it just took a long time for the engine and exhaust system to 'dry out'?? (It is no help that the car does not go on long runs for weeks at a time - just short, stop, start journeys).

There was (is) in fact two other problems - the insulating cover inside the dizzy is cracked in two places. This does not seem to present a problem when the engine is warm and not under serious load - however when cold, or towing, the spark seems to be arcing to earth through the cracks and into the distributor body - the new cover is due tomorrow so that will be that one sorted.

The second problem is LPG related - when replacing the main induction pipe from the air meter to the plenum chamber I took off the LPG backfire protecting thingy to reseat it. This is simply a machined alloy ring with a hinged flap inside - the flap will hinge open when air is being drawn into the plenum but, when there is a backfire, the flap is blasted shut against a rubber seal and the backfire gasses have to escape elsewhere (breather pipes etc.) By chance I noticed that the flap was only able to hinge open about 40 degrees - it was being blocked by a raised lip in the alloy casting, this would explain the feeling of the engine being 'held back' that I mentioned in another post. However I am at a loss as to how this happened - I believe it may be because the backfire damaged the flap hinge in some way but I am getting a new one of them in to replace this one (much cheaper than a new air meter).

Hopefully the car will be back on the road by this time tomorrow - that gives me two days to test drive it before I have to tow around two tonnes for 250 miles on Saturday - that will 'kill or cure' methinks

Graeme

hole/crack/whatever?

Reply to
Graeme

On or around Tue, 9 Dec 2003 20:00:58 -0000, "Graeme" enlightened us thusly:

indeed. don't run it without one.

had a few backfires on my ford which has such a thing, after about 5 or 6 such, it blew the flap such a funny shape that it wedged in the hole. Had to take it out and hammer it flat again, and re-make the hinge shape. On mine, it's only a bit of ally with a pin through one side, easy enough to remove/straighten.

Reply to
Austin Shackles

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