Boiling over but not hot

[H munster]

Kinda stumped here guys. Got a 94 ex for my daughter that i thought had a bad tranny based on performance. After driving it a little i ended up finding a bad head, it was cracked on the exhaust port. Since my daughter will be driving it and we live in the desert i decided to completely do everything right. I replaced both heads (new) all new gaskets, had the injectors cleaned and tested, new radiator,new fan,new fan clutch, new t-stat, new radiator cap,new belts and hoses. The problem now is that when i shut it off occasionally it pushes water out of the overflow container and the engine isnt hot. It runs pretty cool. Any ideas?

 

[mcelwajy]

This may sound completely retarded, but it sounds like you have too much coolant. If the resevoir is over the "cold" line when the motor is truly cold, drain some of that coolant. Hope that helps with out me making you sound stupid...I didn't mean to

 

[Maniak]

Here in southern AZ I have found a 16 lb cap works much better than a 13 lb radiator cap. When I use a 13 lb cap it tends to release the pressure too early. Also, when the vehicle is turned off you get heat soak which makes the coolant hotter, which increases the pressure which will make it go into the overflow some (not a lot).. that isn't a problem as it will get sucked back in later.

Another benefit of a 16 lbs cap is that that it raises the boiling point by 9 degrees over a 13 lb cap. In general, 1 psi is a 3 degree raise in boiling point.

~Mark

 

[JTX]

Do you have coolant in it or just water? Or 50/50? If you put to much water and not enough coolant i beleive that could cause your problem.

 

[H munster]

I am keeping up with the correct level. Dont worry about making me look stupid, my wife reinforces that daily. I too am using the 16# cap and straight water. Never heard not mixing coolant would do this. Have had my BII for close to 10 yrs and it has never seen coolant and no probs. When it does this there is a boiling sound but the engine is not hot. Verified w/ temp gun. If it matters the t-stat is 140 degree

 

[Maniak]

My guess is you are loosing pressure somewhere.. Check for a leaking hose and do a pressure test on the cooling system and make sure its holding pressure. Use one of those things that screws onto the radiator and lets you put pressure into the cooling system.

It doesn't take much of a leak to lose pressure. I have a slight pressure leak where my coolant sending unit goes into the house (aftermarket). It doesn't leak enough fluid for me to see it leak. I only found it becuase it was getting dirty there becuase the dirt would stick to the residue on the hose that I couldn't see.

~Mark

 

[H munster]

Im not sure i follow you here. Are you saying that if i had a small leak that it would suck air in, thus pushing water out? If you are that is a very interesting concept.

 

[Maniak]

Not quite.. If you were loosing pressure somewhere the boiling point would lower as the pressure lowers.. every 1 psi is 3 degrees.

BUT.. if the pressure lowered then there is less chance the coolant would come out the cap..

BUT...

if the pressure was increasing becuase of heat soak you could go past 16psi (assuming the cap really does release at 16 and not 15 or 14) and then the cap would let pressure out, which would lower the pressure some which would allow the water to boil...

After writing it, I'm not sure you could have a leak in the system since it would drop the pressure and cause it to boil, but not come out the cap and your seeing some out of the cap.. Sooo.. It could be normal assuming its not a lot of coolant (water in your case) and there might be some air trapped in the system which could make the gurleing(sp?) sound.

I'll let someone else take it form here as thats the only thing I can think of..

BTW.. you should have some coolant in the system, not for boil protection, but for lubricant.. I usually run < 30% coolant.

~Mark

 

[///Manuel]

1. Measure the coolant temp.
2. Is your fan clutch working?