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Old 10-05-2009, 01:28 PM   #3 (permalink)
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Originally Posted by blueflame View Post
A couple of times I have bought cars with leaking cooling systems that have responded very well to additives in the coolant that allow another couple of years on an older vehicle that would have been otherwised scraped.

What I'm trying to figure out, is the best product specific to the type of head gasket fault, as there are different types of products which may work better with different problems/situations.

1 Small amounts of water entering the oil causing creamy scum on the oil filler cap and upper surfaces of oil pathways.

2 Large amounts of water entering cylinder/s causing quick loss of coolant and overheating

3 Oil entering water causing oily residue on radiator cap and overflow reservoir plastic bottle, but no loss of coolant.

etc etc etc

Some products are like a porcelain, others like copper fillings, silvery fillings, etc etc.

Was wondering if someone could point me towards a tutorial or has good knowledge of this type of problem.

I was also wondering whether re torquing the head would work. Like say #3 cylinder had water cleaning the sparkplug, would re torquing JUST around #3 be a good idea? Or, try an additive first and if that doesnt work try a re torque?

Quite useful to know this stuff, especially if your miles from home and need to get her back without MASSIVE costs.

I religiously change/flush coolant in my own cars, but you never know.

A definitive guide on this subject would be really useful to a lot of people. Lots of products and instructions online but little of what could be referred to as an unbiased and concise report.

(1) Generally speaking from 30+ years in the biz. "Creamy Scum" on the oil cap and the top of the VC (when removed) or the dipstick can be attributed to condensation in the crankcase. Condensation occurs all the time. The vehicle needs to get to operating temperature for a period of time to vaporize this and then send it to the intake, via the PCV system, for removal. Seldom (?I think twice since 1977?) have I seen this minor moisture as an indication of a blown head gasket.

(2) Definite head gasket failure. No product that can be added to the coolant will repair this. The one you mention that produces a porcelain like coating on the inside of the cooling system will slow down the coolant loss for a while, but eventually will break down enough at that area to be rendered useless. This is what used car lots do to sell an otherwise unsaleable vehicle. The purchaser will have to replace the head gasket after his 29 day warranty runs out. This product also requires a LOT of prep work and the offending cylinders spark plugs removed to even work in the first place.

(3) Not usually caused by head gasket failure. Yes occasionally, but in the head passages coolant usually has more pressure than oil. Most of the time I see this when the front cover gasket fails and allows the oil passage from right behind the pump to leak into the water passages in the cover. The oil pump and water pump in the front cover have passages separated by gaskets, when the gasket gets old and fails the higher pressure fluid will move to the lower pressure fluid. Which goes where is determined by where the gasket failed and whether it is on the intake side or output side of the pump(s).

(A) The porcelain product requires the draining, flushing, cleaning and product application into the cooling system. A process that take several hours of work and then allowing the system to sit drained and open for 24 hours to cure the coating.

(B) The silver and copper flakes are exactly that. Flakes of metal. They find there way to your external leak (radiator pinhole) and pile on top of themselves to fill the hole. Good for a small external leak in a car you won't keep. Be cautious, if you have air in the system and use these, they will clog your heater core passages.

Re-torquing a head gasket is not necessary with today's gasket technology. I have not had a gasket failure fixed this way. I have also not had any success with doubling the gasket on a warped head. Others may have had different experiences.

When you are courting a nice girl an hour seems like a second. When you sit on a red-hot cinder a second seems like an hour. That's relativity.
Albert Einstein
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blueflame (10-06-2009)