Discussion
Here's one for you. my car is throwing coolant out into the expansion tank that is foaming especially if i give some hammer. now i had my cylinder head gaskets replaced last year so i assume it's nothing to do with that. i have also bled the system to make sure there is no air in the system. any ideas guys?
Hi Jon..It shouldnt be a head gasket but it might be worth having a hydro-carbon test done anyway and there is no garauntee that it was done properly..What colour is the foam?..It also sounds like the system is not pressurising which means there is a either a leak or Blockage somewhere..Have you checked the rad cap and expansion cap?
I've got a similar problem. When pushed hard, water is ejected out of the water bottle
despite the fact that the water temperature is pretty normal
Where can I get a hydro carbon test done? Is this done when the water is being
chucked out, or would there be enough residual hydro-carbon in the overflow
tank for it to be tested cold?
Dave
despite the fact that the water temperature is pretty normal
Where can I get a hydro carbon test done? Is this done when the water is being
chucked out, or would there be enough residual hydro-carbon in the overflow
tank for it to be tested cold?
Dave
I hate to say this but on the two occasions I had this (different engines and vehicles) it was a blown head gasket. The foam is typical of a leak somewhere from the cylinders as far as my experience goes. Tends to foam more and blow out coolant on heavy throttle application, and both mine ran hot some of the time, and not at others. I reckon air bubbles in the system caused overheating at some points ?
One engine (2.3 Ford V6) had corrosion on the block surface, so even a new gasket didn't solve the problem for very long.
One engine (2.3 Ford V6) had corrosion on the block surface, so even a new gasket didn't solve the problem for very long.
Edited by RCK974X on Tuesday 9th April 22:30
Dave Meredith said:
Where can I get a hydro carbon test done? Is this done when the water is being
chucked out, or would there be enough residual hydro-carbon in the overflow
tank for it to be tested cold?
Hi Mate..A good garage should have a tester..If there is hydrocarbons in the coolant you will smell fuel in the expansion tank, Normally when warm/hot..If it is happening then you will get it anytime you top up or replace with fresh coolant..Or at least i did with mine...Not sure about when cold though?...Zigachucked out, or would there be enough residual hydro-carbon in the overflow
tank for it to be tested cold?
I had this on my 350i, took me ages to sort it out but I got there in the end. It turned out to be several very small leaks in the cooling system (pinholes in the heater pipes and distorted/corroded hose spigots preventing the hose clips clamping down properly). The small leaks were preventing the cooling system from pressurising correctly so the coolant was boiling in the cylinder head passages even though the temp gauge was reading normal. The small leaks were also allowing air to be drawn into the system when the system was cooling; resulting in repeated air locks forming.
The leaks were so slight that the coolant was evaporating off quicker than it was leaking out, so they were difficult to spot. I eventually found them all by starting the engine from cold; running it for a couple of minutes; shutting it down and then looking very carefully for damp patches around all the potential leak points. Each leak wasn't particularly significant on it's own but put together they were combining to cause this problem.
The way the standard cooling system is set up, there's a pipe from the hot side of the thermostat which goes to the plenum heater then into the expansion tank. The hot side of the thermostat is the highest point in the system so any bubbles forming due to cyl head passage boiling or air locks goes to that point, which then appear as bubbles/foam in the expansion tank. This pipe also causes the level in the expansion tank to rise, but that's another story!
The leaks were so slight that the coolant was evaporating off quicker than it was leaking out, so they were difficult to spot. I eventually found them all by starting the engine from cold; running it for a couple of minutes; shutting it down and then looking very carefully for damp patches around all the potential leak points. Each leak wasn't particularly significant on it's own but put together they were combining to cause this problem.
The way the standard cooling system is set up, there's a pipe from the hot side of the thermostat which goes to the plenum heater then into the expansion tank. The hot side of the thermostat is the highest point in the system so any bubbles forming due to cyl head passage boiling or air locks goes to that point, which then appear as bubbles/foam in the expansion tank. This pipe also causes the level in the expansion tank to rise, but that's another story!
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