Itoyota

So ... I have been getting condensation on my oil cap ... I have been attributing this to the sub zero temps + Old block+ and short trips which will cause some pancake batter mix buildup on the oil cap only. When it warmed up here and i took it for a long drive the amount of condensation decreased significantly.

Secondly, the coolant level has just recently gone beserk. The level would rise in the resevoir then after stopping the truck would bubble from the hose sucking coolant back into the radiator.

I SUSPECTED A HEAD GASKET LEAK ... but am now thoroughly confused as a Compression check has yeilded solid results bringing back 190 PSI in every cyllinder with leakage at a stable rate equivalent across all 4 cyllinders.

I also vacuum gauged the Intake Manifold and found no variance in pressure at idle. A solid 17 PSI w/NO SHAKING of the needle.

So what's up with this?! The timing cover has recently been replaced with a brand new casting and the HG is less than 5k miles old.

Your input and brainstorming is much appreciated.

stumpjumper

Try a new rad cap,same thing happened to mine put on new cap problem solved..

Itoyota

New radiator cap same issue.
Problem persists. I've got pressure building in the radiator air circulates through the heater core during operation ... so the gas bubbles are seriously large as I notice a temp change in the heater vents.

BUT the temp gauge never budges ... the cyllinders all have compression w/little leakage that is the same across all 4 cyllinders.

IS THERE ANY WHERE ELSE WHERE I CAN BE GETTING THIS PROBLEM THATS NOT THE HEAD GASKET?

thanks

Itoyota

HELP!!!!!! PLEASE!!!!

Can it be the intake manifold/throttle body? Coolant runs through there but can that allow pressurized air into the cooling system?

Can a leak into the vacuum of the IM cause air to fill and pressurize in the radiator?

I ran the engine with the cap off and watched the radiator bubble air up every once and a while ... i know that normally means HG leak ... but my compression levels are awesome? It's never overheated ... and it's a new Rock auto HG?

abecedarian

It's normal for coolant to flow into the reservoir (expands as it warms) then return to the radiator (contracts as it cools). So I'm confused.
When it warms up, does it blow bubbles into the reservoir? ... or do you just hear bubbling as it's cooling off? After it cools off, how is the coolant level in the radiator after it cools off? ... the reservoir?

93toyrunner

did you ever check your fluid before starting it when really cold, maybe your freezing point is right where it is crystallizing and little frozen chunks through out you system then when hot they all start breaking apart and blasting through

Itoyota

The amount of coolant exchanging places between the resevoir and radiator is NOT NORMAL we are talking about 1/2 the volume of the top tank on the radiator. The bubbles I last posted were IN THE RADIATOR at the neck so i now suspect HG leakage ... but No one seemse to be able to explain my perfect compression numbers.

abecedarian

the volume of the upper tank in the radiator is about 8... no I'll give you 16 oz / .5 litre at best- about the size of a medium soft drink at McDonalds...
... and you're talking about 1/2 that- about 1 cup of coolant?
You're paranoid.

It takes a little over 1 gallon to fill the whole cooling system up. 1 gallon being 128 oz / almost 4 litre.

Itoyota

You're not hearing me ... and Im not paranoid ... Leak down is showin HG leak.


So thanks anyway abecedarian.

Itoyota

I just removed and checked the thermostat ... it's good.
Drove the truck around got it nice and hot Normal Operating Temperature ... then notice that the radiator overflow tank was bubbling not boiling ... the line that goes to the radiator to fill it back up when coolant level is low ... was bubbling into the reserve.

abecedarian

if leakdown's showing headgasket, then that's probably the issue. that does explain your last post- getting bubbles blowing into the overflow.

arizonaguy

did u pressurise the cooling system yet with a pump to purge out any air in the system??

Itoyota

yes i did pressurize the cooling system ... there is a leak internal (cant find a leak outside the engine) the air is not from bubbles that need to be purged ... they are bubbles sneaking themself out from the HG ... This I am almost 100% sure of .. I just wish someone can say- (yeah ... that's a HG. Mine had great compression numbers ... hardley smoked at all ... bubbled in the overflow tank and ran like a clock)

So ...

abecedarian

No one is going to tell you with absolute certainty that the head gasket is the problem unless you can adequately describe the situation... but you did: you yourself said:
...so why should anyone vilify or even verify your claim?
Presuming it was a proper leak-down test, the results are nearly incontrovertible so what other proof or justification do you need? ...unless the leak-down test wasn't a true leak-down test and.... nevermind, pure speculation on my part.

Itoyota

cuz you see ... college students that are going to med school dont like tearin into the head of their everday driver and not having a backup car. I guess what I'm tryin to say is ... there HAS been too much speculation on others' parts ... and I'm just lookin for some clarity and assurance. I'll look to a gauge instead of people ... they don't speculate.

;-)

thepartsguy

It may not be the head gasket yet...

Check the lower radiator hose if it is spongy the pressure from the water pump pulling on the hose may be sucking it closed.

Check to make sure the new cap is holding pressure

Is there a change in how the engine temperature gague is behaving. You said you only drove it short trips, does the needle on the gague behave oddly when you drive for extended periods of time (i.e. heating up then cooling, then heating up mre than before, then cooling, then maxing out the gague.)

if the head gasket is leaking you should notce a black gritty mud settling in your overflow tank.

turborich

Just some info. I once had an engine that would slowly get warm & eventually build up so much pressure that it would overheat. No water in the oil or tailpipe but had exhaust fumes in the radiator. Somehow the exhaust was leaking into the cooling system but not leaking water into the oil/exhaust. Is this happening in your case?

Itoyota

yeah ... this is actually really helpful guys. Thanks! I am pretty sure its the HG as I am building pressure in the radiator ... and after the really really really cold spell we just had up here in Northern MN ... the oil began to get contaminated with water more than before. Sucks to be me ... but I have a decision to make here.

Fel pro gasket set ... ?
Rock auto gasket set... ?

I've used both ... but this rock gasket was the one that has just blown so soon.

I think the block may be warped as this HG issue has been incessant.

abecedarian

This IS going to come off sounding wrong but... you're pre-med? Since when has medicine required absolute proof that something is wrong? Everything about diagnosing some medical condition is based on the patient's statements and some tests and inference based on some previously recorded notions, preconceived ideas, experience and deduction.

All we have here is the patient- your truck, and the information you offer to us (which we have to take as face value due to lack of being able to witness the events, readings and measurments ourselves).

No one here is going to tell you straight-out, point-blank, that "X" is your problem, in much the same way as a doctor wouldn't tell anyone that their weight gain is being caused by hyperthyroidism as opposed to "hypermacdonaldsism" unless one could perform the tests themself or have first-hand or similar access to the test results.

I sincerely hope you return your truck to proper operational status.