280i overheating.

[sjp76]

Ok, I've had loads of problems with my cooling system lately. I've reaplaced all the hoses, the viscous fan, the water pump and thermostat and taken the rad out and flushed it (no blocks or anything). After doing all this, the pressure was still building up way too high and the pressure cap was blowing. I've just had the heads stripped down and gaskets replaced. but still the problem persists. I'm wondering whether there may be a crack in the block which is leaking pressure into the water jacket, and I'm thinking of a recon engine. I obviously don't want to spend all that money, before I've exhausted every other possibility. Is there anything I've missed. If i'm gonna have to replace the engine, I wanna make damn sure its going to solve the problem. Help please!!!!

[danny hoffman]

Have you had the system pressure tested?

[wedg1e]

Donkey's years ago I had a Spitfire, and apart from the fact it did 420 MPH and would climb to 22000 feet in 2 minutes, er..... sorry, I'm rambling.... ;-)
Anyway, I had the engine in bits, and I had to refit the head three times before I got a head gasket that would seal properly. Of course that was some prehistoric Standard-Triumph engine and not a state-of-the-art Ford V6 ;-) but if you had cheapo head gaskets it may still be the cause. Also, if the head bolts weren't torqued correctly at last rebuild.
Failing that, have you had an unleaded conversion, 'cos sometimes they manage to break into the water jacket when they machine the heads. Strictly speaking that would scrap the head, but if they didn't notice....
Failing that, how about ignition timing casuing overheating?

Hope it's nowt severe!

Ian

[sjp76]

Guys,

I've had the engine pressure tested. with the engine still hot and the system depressurised comnpletely at the start, system gained about 8lbs in a few minutes. That sounds sounds like a lot to me, considering any pressure caused by water expansion would've already occured and been released, but I'm no expert.

The engine does run on unleaded, but used to run fine even after the head conversion, so can't see that the head has been damaged when this was done.

Ian, can you explain the timing theory please.

Cheers,
Steve.

[danny hoffman]

I don't really inderstand why the pressure would drop when the engine is started (unless as when the water starts to cirulate it cools down and that reduces the pressure?)

Anyway if the ignition is wrong it can make the engine run hot, to far advanced I think.

Danny

[sjp76]

The advanced timing may well cause it to overheat, but I didn't think it would account for the large and rapid build up in pressure in the system. Wouldn't that have to come from the engine somewhere?? Its really weird cos theres no water mixing with the oil, so possibly there's a crack between one of the cylinder walls and the water jacket??

[wedg1e]

I saw some info on a website (may have been RPI) that suggests the V8 block can crack behind the liners, causing an assortment of problems. Might be worth a look. Bit of a c**t if it is that as it writes the block off.
I was thinking of over-advanced ignition causing the problem, but I doubt it's the case now with the pressure symptoms you mention. Does sound to me like something cracked or not sealing properly. Hope I'm wrong. I know the pain of taking a V8 to bits when you thought there was nothing wrong with it....!

Ian

[wedg1e]

DoH!! Ignore my last; I was forgetting we are talking about a V6 here.... Berk.
Erm... still sounds like a leak though but....

Ian

[sjp76]

Cheers Ian,

Found what looks to be a good company that specialises in Ford engines (specialisedengines.co.uk). They invite you to come down and see the build process which I like the sound of cos it means they've got nothing to hide. I'm looking at around 1500 quid including fitting. Not the cheapest quote but worth it for piece of mind. Everything is crack tested and, if i prefer and don't mind waiting a week, they'll recondition my lump rather than replacing it with another one. That way (assuming the block isn't knackered) i get to keep the same engine number. Sounds good to me, Just hope it sorts everything out. What do you think?

Steve.

[M@H]

I was amazed at how hot an engine can get if you get the timing wrong.. I set the timing too advanced on a 1200 beetle engine, and there was soon oil smoke coming from all over the place, including the oil breather pipe and oil filler neck when i removed the cap to check it out... nearly killed the engine so I'm quite keen on ensuring timings set right...
Cheers
Matt