cetrainor

Hi Bill,
Yes......I installed a pressure tester and ran the car up to 14# and the tank was full to overflowing into the catch can. What I was trying to point out , was the differential between coolant temp (~180) and the coolant pressure.
In the end.... I have lot's of system pressure (overflowing) and normal engine temps.

Thanks'
Coleman

2002maniac

Ever get this figured out? I think we may have similar problems.

Mrmerlin

sorry this is a bit vauge, can you add more detail??
things to check visual,
look at the top right of the radiator where the top of the end tank meets the core for white deposits that indicates a leaking radiator.

remove the aircleaner and inspect the heater control valve and short hose for leaks, also the left head rear coolant block off plate same position as the outlet for the HCV.

Inspect the coolant bottle for yellowing or cracks or deposits around the bottle and metal spigot, white deposits mean its leaking.
Look at the top and bottom of the oil pan in the center for dried coolant this indicates a leaking waterpump.
Look for dried coolant on the bottom of the AC compressor, this is a leaking waterbridge or hose.
Inspect the pressure switch about 4 inches in front of the coolant bottle for white deposits
If no leaks observed then replace the ...

HCV and short hose.

thermostat, front O ring and rear thermostat seal,

install a new pressure cap they are good for about 5 years

Drain out the coolant and replace it with new coolant
I suggest Zerex Z 05 at NAPA (drain the block it holds about 2.2 gallons). Road test, you never mentioned how you tested for hydrocarbon in the coolant .
NAPA sells a block tester for 50.00 well worth what it can diagnose
To fill the system add the coolant and distilled water,
with the cap off run the engine till the fans come on and the heater on full hot, make sure the coolant is at the seam or above it replace the cap and drive the car for about 5 miles then park it let it cool off top up as necessary.
Please report back what you find

cetrainor

Maniac,
No I haven't gotten this figured out yet. I'm sorry to have dropped the ball but I had some external pressures that put this project off for a while.

Merlin,
Thanks for the list of things to check, but I've looked at most of these. I have in the past had a tiny leak that is unrelated to my current problems. I am losing fluid at the expansion tank, confirmed with a catch can.
Sorry for the vague response to Bill that you quoted............... what I meant to say was, I'm losing coolant from the expansion tank. I put a cooling system pressure tester on the expansion tank with a gauge and ran the car until the pressure was 14 pounds or so at which point it overflowed into my catch can. The confusing part is I have normal operating temperatures at the water bridge and thermostat housing etc. 180° to 185° or so. Yes I tested for hydrocarbons with a NAPA block tester.

I'm in the process of installing a new water pump and timing belt (it was about time anyway). I thought perhaps the impeller might be slipping but after removing the old pump, that doesn't seem to be the case.

One interesting side note is, when I drained the coolant from the radiator and from the two block plugs I only captured 3 gallons of fluid. Maybe there's some still in the heater core. I flushed everything with a garden hose and didn't see too much crud.

I guess my next thing to examine is the radiator flow.


Thanks for the input,
Coleman

Mrmerlin

you should get close to 4 gallons out of the cooling system make sure to drain the block after flushing it holds about 2.2 gallons all told the radiator holds about 1.4 gallons and the heater core should drain when the top rad hose is removed.

If you have a leak at the coolant bottle it would be best to fix it as it wont let the coolant system see proper pressure this can result in boil over, also check the fan for resistance if it free wheels then it needs a new fan cluch

To fill,
add coolant to the car while its level run the car with the heat on,till the fans come on, and the cap off install the cap then drive the car with the heat still on for about 5 miles then park it let the system cool off then top up as necessary

blown 87

Regarding the chem checks for hydrocarbons in the cooling system, they can only prove that hydrocarbons are there, not prove they are not.

Many times a small leak like that can not be found using a block checker.

cetrainor

Thanks Merlin,
I don't have a "leak" at the expansion tank. It is coming from the overflow tube and into a catch can I made, to verify.

Greg,
Are you suggesting I may have combustion gases in the coolant that don't show up because the amount is too small to be read by the block chem tester? For what it's worth, the plugs read okay.

In the end I still have enough pressure to blow coolant out the overflow tube but have normal operating temps.... ~185 at the water bridge.

Installing a new timing belt and water pump today.


Thanks for the help,
Coleman