head warp

[wengr]

hello, if the head gasket fails as a result of overheating, (bubbles in coolant, no contamination of oil, no exterior leaks) will the head definately need to be resurfaced? how does one tell if it's been cut before and how much is too much?

[So Cal Mark]

Fiat makes a tool that fits into the combustion chamber to measure head thickness. If the gasket is blown, more than likely the head will need to be surfaced. To check it, place a straightedge on the clean head surface and use a feeler gauge to measure for low spots

[wengr]

thanks Mark, any tips to verify the head gasket condition short of the typical exhaust in the coolant sensor probe which is not available to me? car is an 83. the car did overheat recently. why I suspect it is when started from cold with the rad cap off, some bubbling is apparent and the level rises some what quickly. also with the plug out of the tee piece on the front of the head, bubbles are very apparent and the level rises up and out immediately. also of note, seems like somewhat excessive moiture from the exhaust pipe. steam and even droplets that form a wet area behind the muffler. the thing is, it is clear and does not smell or taste of coolant. the car has 78k and is new to me. I'd hate to pull the head for no reason.

[So Cal Mark]

can you pressurize the cooling system? Usually a leaking head gasket will cause a misfire when first started. The first place coolant will show up in the oil is the underside of the oil cap. If you have a milky looking goo there, expect a leaking head gasket.

[rlux4]

I had a problem overheating last year on a trip from So Cal to Oregon. I suspected a blown head gasket, and replaced it. Turned out it was OK after all. The little gasket at the water pump at the tube to the heater core was leaking. It's on the suction side of the water pump, so when the car ran it pulled air in. Some PO had cut off the bracket on the pipe that hangs it on the underside of the manifold, so it wasn't being held steady. It's a long shot, but it could be happening to you also.
Ron

[wengr]

Thanks Ron, never thought of anything like that. I'm never that lucky but I'll check it out. Some more questions - What is the value of "head straightening" for our cars. how do you know if the cam bores, etc. are still good enough?

[rlux4]

Like I said, it would be a long shot coincedence, but I didn't think of it either until I pulled the head and it and the gasket were good, when I put the new head gasket on, it still overflowed the coolant from the air displacing it and overheated. BTW, one symptom was air bubbles coming up in the radiator.
Ron

[wengr]

What I'm thinking is, as the water pump on my car does not sound so great thru a mechanics stethescope and the pully wobbles a bit more than I'd like, for the low cost of them I'll put a new one on and that should rule out any problem there.

[So Cal Mark]

the water pump pulley shouldn't wobble at all!

[adrians]

I had a blown head gasket in August last year, the symptom was the lower radiator pipe remain cool when the engine temperature was high, because the thermostat wasn't receiving enough hot water to open the thermostat. Also I was using 0.5l of water on every 30 minute drive, temperature gauge was showing just under the "RED"

[So Cal Mark]

the reason the t-stat wouldn't open is that exhaust was getting into the cooling system and displacing coolant. So you constanly get an air bubble at the stat

[TulsaSpider]

If there is an advanced auto parts in your area, they loan out, with deposit a cooling system pressure tester. You might try that to see if you have any leaks, and pinpoint them.

[wengr]

If there is an advanced auto parts in your area, they loan out, with deposit a cooling system pressure tester. You might try that to see if you have any leaks, and pinpoint them.

thanks for the tip, sure enough my local advance had it. I'm going to try it today, but don't expect a good result. so if the head comes off, should I worry about straightening, or just the shave and reinstall? Is the Vick's high performance head gasket worth the extra $$ or will any one do? thanks in advance

[manoa matt]

Bayless sells a high performance head gasket for $20, its pretty thick, has a good amount of metal reinforcing between the rings, but does not have any of the pre-formed silicone on the surfaces. Try to stay away from the "Tako" head gasket that is typically sold by the vendors, it has red silicone on the top surface. Autozone and Parts America a.k.a. o'riley, checker, chucks, cragan, and murray's all sell the Fel-Pro head gasket, which I've heard good things about.

[wengr]

Ok I give up. parts are on the way and the head is coming off. My best guess is that I can bleed forever as the head gasket keeps injecting air. I'm liking the idea of pulling it complete and dissassemble on the bench. this raises two questions:
is it easier to remove downpipe to exhaust manifold bolts from above or below? if below what's the prefered method for raising the front? will ramps foul the fenders? or if it's stands where would you place the jack and stands?

also, for resurfacing can I cover the chambers with tape or something and leave the valves/injectors/cams in place for the milling? or will it need complete dissassembly?

ps - Ron, a pressure test showed some small leaks but none at the waterpump pipe joint that you mention. the pipe is secure and I don't believe it's drawing air there. thanks for the idea.