Unusual Coolant loss - possible fuel contamination

[WagonLover]

'91 Corolla Wagon, 4AFE engine, head gasket replaced a year ago, over-torqued head by 5 lbs. Ran great, no coolant loss. Moved from San Diego to Portland and in Dec. system started to lose coolant. Used Barr's Stop Leak (Aluminum) and then 1/2 can of rhizone pellets. No stopping it. It would never lose more than a quart and never overheat - just run hot - 50% where this engine would normally run around 3/8th's (original engine ran at 1/4 to 1/3 on temp. gauge).

Pep Boys replaced it under warranty with a different manufacturer (coolant tube split obvious when rad pulled as "oil" from stop leak rhizone tabs stained the front of radiator where not visible). New Radiator seems ok.

Go to SoCal to pick up storage and the further south I get the hotter the engine runs. Losing coolant - in fact - blowing it out the overflow tank all over the engine. Limp back to colder Portland after changing out thermostats with no change.

Pressure test rad caps - all spec even old one - 13 -16 lbs. with Moto Rad Tester from AutoZone. Pressure test system no leaks. Still when it gets to operating temp it blows out coolant overflow.

I tested the therms in boiling water and they do open (even though they are not under pressure in a system) even the original. My roommate has an '89 Toyota pick-up with a 22RE. Same radiator cap -13 lb. system. I mic'd the factory rad coolant fill hold down and it measures 5.3 mm. It's Metal. My aftermarket 1 month old rad mic's out at 4.5 mm. When I wedge a 1 mm piece of plastic under the tines of the radiator cap, I lose no fluid out the coolant overflow tank (makes it the equvilent of a 5.5 mm stop depth).

My brother works with injection moldings from China. Poor Quality combined with the natural inclination of molds to deteriorate over time coupled with a shrinkage in plastic if not cooled slowly (massive vs. mass production). I spoke with the mfctr which is Proliance and they acknowledged ther could be a problem, but the engineer did not have a spec sheet in front of him (OEM, Right?!) and could not be certain. Now, neither they nor the PepBoys Manager will return my calls.

I went to the U-Pull_it and found a good OEM style all metal radiator (Modine) that does not leak and installed it this weekend. It runs cooler and loses less coolant (2 cups vs. 1 quart in a 6 quart system) but I would swear that the rad smells of fuel which does not make sense. There has never been any foaming in the oil, the water pump only has 30k on it and shows no sign of leaks and there appear to be no other leaks in hoses etc. Occasionally I've smelled coolant coming through the fan - but it does not seem to be the heater core.

Ideas? How can I get fuel in coolant? Isn't coolant under greater pressure than fuel system? Where could leak occur? It would have to be in the head somewhere, but hwere and how? Warm, and pressure tested the system loses pressure very slowly, but it could also be related to pressure equalization because I have an air gap when releasing a hot radiator cap and it takes longer to pressurize a system with air in it.

Thanks,

Wagon Lover

[toyotaspeed90]

the radiator could have come from a car with a BHG or other issues (ie a stuck open injector as well) -- fuel can contaminate the oil which can get into the coolant -- it would all depend on how the PO took care of it.

Also, if you didn't pull the rad and it was sold to you directly off the shelf, it isn't uncommon to use acetone to clean oil coolers -- wouldn't be surprised if someone ran acetone through the rad.

As for the coolant loss there is one of 3 things going on.... you have a slight HG leak. This is either causing combustion to enter the cooling system (creating bubbles, which overheat easily, then you lose coolant through the overflow tank) or it is slowly burning coolant off until the engine warms up and the gasket expands, closing the break (which yes can happen -- and most people just see that as condensation burning off). A 2nd possibility is that the coolant system wasn't bled properly and had an air bubble... if it got trapped in the engine it could have easily overheated, causing excess pressure then overheating of the coolant, at which point it will come out of the overflow tank. Lastly, the overflow tank is hooked up wrong and at RPM's above an idle it's slowly filling the bottle and overflowing it.

[WagonLover]

The problem with the overflow tank was fixed by putting in a used all-metal radiator. Has anyone had experience with out of spec radiators? Anyone get resolution from a manufacturer? or retail outlet?

Cold engine - no leak, warm engine - slow leak, warm engine running while pressure testing system - gradual increase in pressure.

I hate to do another headgasket and am worried that maybe the head cracked somewhere which is why the coolant smells like fuel (I pulled the rad and it was covered with that white citric coolant system cleaner). I pulled the plugs and could see no scouring of the top of the cylinders.

Can I seal it some other way? It doesn't seem like many here speak well of stop leak type products.

Thanks for the feedback!

[toyotaspeed90]

I would only use stopleak in a car that I planned on changing the motor, radiator, and heater core....

I pulled an engine from an mr2 that someone had used it and almost all of the coolant passages between the block and head were closed up.....

I've used aftermarket radiators (cheap online stuff) with no problems -- my ae92 has had one for about 6 years and has plastic top and bottom portions, friend of mine has used an all metal $60 civic radiator with no problems as well.


There should be an increase in pressure.... to a point....
You could pull the rad and take it to a local shop to have it flow tested as well.

[WagonLover]

Well, I've already used stop leak in it. My budget is the problem. Gaskets will run me $90 (head, intake, exhaust). I've already got injector seals. Supposedly the 4AFE uses non stretch head-bolts, but I bought new ones for the head job 10k miles ago, so I probably don't need to replace those ($48). Would you over-torque again and if so how much? Machining the head with a cleaning might run me another $90 without a rebuild (the machining of this head originally had no leakage in pressure test). How could I clean existing components of stop leak (which was used in this metal radiator, as I see it float around and stick to the radiator cap gasket!).

As for the plastic radiator. The "stops" on the metal rad hold the cap down approx. 5.3 mm. The plastic ones I've measured (only a couple) at the junk yard measure 4.9 mm (You can feel the wobble in the cap much more in an all palastic!), but my new replacement measures 4.5 mm - that's 0.4 to 0.9 mm difference at 13 - 16 psi. In other words, I'd love to say I was screwed by someone else, not me - ideas? Or just suck it up and get on with it?

Thanks,

Doobs