accel

Hello,

I've recently experienced some pretty "funny" situations with coolant being pushed to extension tank _sometimes_. The coolant temperature is normal, i.e. - the engine does not show signs of overheat. No signs of coolant in oil.

This has happened twice, both times the car was going through mountain passes with 4 passengers and full trunk of load. The amount of coolant that is being lost is moderate - comparable to 16 oz water bottle, and mountain passes were long ones - so it was taking me around 30-60 minutes to get through them.

First time this has happened (around a month ago), I spotted coolant leak under the front of the car right after the mountain pass when I stopped to refuel the car. The ext. tank was full, the coolant in it was not hot, and the radiator and hoses' temp. was not extremely hot.

I replaced the thermostat (just in case), radiator cap, ext. tank cap and hoses between the radiator and extension tank; the dealership investigated the coolant for carbon, and their verdict was - no carbon in the coolant and therefore, the head gasket is OK, radiator fan was also ok ... Flushed and replaced the coolant.

I kept watching the coolant level and everything seemed OK.

Then last week I went for a long trip, and after several hundred miles of freeway speeds checked the coolant level - everything was in the norm. The next time I checked the coolant right after the mountain pass (fw 5 in LA), and again saw the extension tank overfilled with the coolant that wasn't hot or boiling...

Only this time I realized the pattern of mountain passes...

So I kept driving another 200-300 miles back home and upon arrival verified - there was no more coolant push to the ext. tank after the pass...

So, what is it?

The water pump had been replaced a couple of years ago at the time of Tim. belt replacement... The radiator was also replaced around that time as I've noticed the old one had a crack and a leak at the top... The cooling system looks good, no leaks or any other signs of leaks or irregularities...

EJ8_Man

My guess is your head gasket is failing. Under load exhaust gas is leaking into the coolant surrounding the cylinders and pushing coolant into your reservoir tank.

When this happens, under the right conditions, you can smell the exhaust gas in your over flow tank.

I had this exact problem with my 99 EX when it was stock.

accel

This is my thought as well... but the dealership has checked the coolant for signs of carbon... and told me they didn't find them...

S2BumpsticksGSR

Atmospheric press is lower in mts. I'm going w/head gskt small leak. Run w/cap off and watch for little bubbles(if poss, do it in higher elevation w/o burning yourself). The only thing I've ever seen push coolant into tank is h/g. I wouldn't trust their "carbon test"

EJ8_Man

My thought's exactly. Considering your motor just finished blasting a large portion of it's coolant out of the reservoir, and you replaced the lost coolant with new "carbon free" coolant, the fact that the carbon test failed is not surprising

accel

Ok, so I am looking into HG replacement sooner or later.

While browsing the forum not one time I saw posts mentioning that the replacement gasket typically only lasts a couple of years. It is true or misconcept?

accel

My though was - the coolant was exposed to exhausts for only short period of time - so the concentration wasn't high... and then - yes - I added some coolant, not much though....

On the opposite side the dealership was most likely interested in doing HG replacement .... so they'd report even if detected small carbon amounts

grumblemarc

iTrader: (4)

Felpro? Yes. OEM? No.
That's what I've read.