My 02 Accord with 71K miles is losing it's coolant at about 1qt / every two days. It began about 3 weeks ago when my DW was driving and found that the AC didn't work very well, and then she realized the temperature is at the max level. I was told about the problem in the afternoon and had filled the tank and radiator with coolant to their normal levels following all typical procedure to burp out the air bubbles, etc. It ran fine for another week when the high temperature returned, and I refilled the radiator again using up approx. 1/2 a can of coolant (forgot how much coolant is in that can, but it's a typical size, 50/50 pre-mix I bought from Kragen). I've been monitoring the radiator and the tank for the last 10 days and here are some observations:

* Overflow tank remains at full level. One time I found it was slightly higher than the full mark. During the 2 major refills mentioned above, the overflow tank was completely empty.
* Radiator is losing about 1qt per week for a while and increased to 1qt every two days.
* No obvious white smoke coming out for the tail pipe
* No obvious sign of having oil in the coolant or vise versa. However, the bottom of the cap has a coat of milky greasy stuff underneath (I live in California, not a cold weather)
* No obvious leakage found in the engine. No coolant smell, etc.
* Engine is fine, except at one time the Check Engine light blinked but completely went off after the trip.
* The car is a little hesitate when starting on warm engine (i.e. after approx. 1 hour). Otherwise, it starts fine on cold and hot engine.

So I took the car to a local repair shop to do a coolant pressure test. I wasn't there when they checked out the car because they need to wait for the engine to cool down. At the end, they wrote down on the receipt: the coolant pressure test didn't show any exterior leakage and I have a "not so good" head gasket. They verbally told me they found some combustion gas in the radiator after doing some test (what test is this?). They gave me an estimate to replace the Head Gasket, Valve Cover Gasket, Exhaust and Intake Manifold Gaskets, Thermostat, and machining the head to make sure it's flat.

What is the test they mentioned that they have done? Does it sound like they diagnosed to the right problem? Is there anything else I should check before taking it in and paying a large amount of money to fix this problem?

Thanks a lot in advance.

 

Welcome!

Umm, that IS the sign of coolant in the oil.

There's a test where they go a chemical analysis of the antifreeze & look for combustion gas dissolved in the antifreeze.
There's another simpler test where they run the engine with the radiator cap off. Plug the radiator neck with a rubber stopper & hose going to a bottle of special magical chemical solution. It will turn colors in the presence of exhaust gases.

I'd say you have a bad headgasket.

 

according to what you are saying, it sounds like a blown head gasket,,,,,,,,,,,,, but to make sure do a leakage test

 

Somehow when I showed the cap to the mechanic, he said it could be normal to have a milky stuff in the cap like that. I am thinking of renting a coolant pressure tester from a local AutoZone to test to see if there's any external leak on the system. Should I try this? or it's enough evidence to say it's the head gasket and I should bring it in for repair?

Edit: Oops, I was typing the reply and didn't see your message. I will rent the kit and test it tomorrow and report back with any findings. Thanks

 

didn't you say that shop did a pressure test and that there was no outside coolant leaks ???? DO A LEAKAGE TEST

 

Yes, the shop told me that they have done the pressure test, but it's the first time I deal with them and wasn't sure if they in fact did not find anything (I know, I should have done it by myself before taking it in, or at least stay there when they do the test... but I wasn't aware of any of these tests before)

Please excuse my ignorant, but what's the diff between pressure test and leakage test that you suggested? Just want to confirm. Thanks

 

I guess you can get that from condensation even without a HG leak. But that usually happens in winter when it gets real cold at night.

 

I dropped the car off for the head gasket replacement this morning. The shop guaranteed that it will fix the problem of losing coolant. It will take 3 days for them to remove, shave the head, and put it back. I really hope that it will go away.

Some friends told me usually after changing out the gasket, I will still have some other problems, so be prepared for this. I just wonder if this is an accurate statement? What should I look for after taking the car back from the shop, besides checking the water level (as this is the main problem that I can see at this time). Thanks

 

I took the car back today. The shop showed me the gasket which has a leakage between two cylinders (#2 and 3) and between #2 and a smaller hole for the coolant next to it. I didn't see any other leakage between the water holes and the oil holes. Anyway, I hope they have found the problem. The car is running smoothly as before and I hope there will be no other problems due to the overheat. I forgot to clean the oil cap, but will do that when I get home and will monitor the cap and the coolant level from now on. Thanks to everyone for helping on this.