Coolant Overflowing

[dprimo]

OK, here's the story: '92 Lexus ES300 (approx. 200k miles)

A little background....radiator and hoses were replaced about a year ago.

Car is overflowing coolant out of the reservoir, but not overheating. Coolant in reservoir seems to have a yellowish brown tint to it while the fluid in the radiator itself remains green. I added some more coolant mixture to fill it back to the low line in the reservoir and changed the pressure cap (just to be sure). After a decent drive of about an hour the coolant again overflowed upon parking.

The car is running smooth with no issues other than the leaking coolant. The car does have close to 200k miles.

Any help or thoughts would be greatly appreciated. Also, please don't say head gasket. I hate those words. :(

[SKperformance]

first problem is get the right coolant in their

second is replace your rad caps you have 2

[mburnickas]

I assume you mean the normal rad cap and then the one of the overflow reserve.

[dprimo]

first problem is get the right coolant in their

second is replace your rad caps you have 2

I replaced one of the caps, not the one on the radiator itself.

This morning I checked the coolant level and it was just below the low line in the tank and after driving it was just above the full line. The levels looked OK.

I'm not sure on the type of coolant that is in there. I called a garage and they said it was something that should definitely be looked at.

I'd just like to know your thoughts. I've never posted on this board, but I have used it as a resource on several occasions so I appreciate all your help.

[dprimo]

I just replaced the cap on the radiator itself. That cap was very dirty with brownish gritty buildup.

What could cause the coolant to get this dirty in less than one year?

[SKperformance]

if it gets real nasty looking

first make sure it is the red one from toyota not the green stuff

second is their is contaminet in the engine form before that was not removed, it was probably was just drained last time and not flushed to remove all of it the last time

[dprimo]

It is the green. I don't think I've ever had the red stuff. I've used the same Lexus authorized mechanic for some time and I've always been green. I guess my knowledge on this stuff is pretty green too.

Could that be the problem? How important is the "red stuff"?

[psh010]

I'm not going to say "head gasket"; but unfortunately, that is where you may be headed. Take it to your mechanic and have them do a cylinder leakage test on each cylinder. It is a simple test (assuming your mechanic has the tester) that will take about an hour for all six cylinders.

That test will tell you whether you have a leaking head gasket. Good luck.

Also, a 92 es300 has a cast iron engine, so the green coolant should be OK.

[SKperformance]

I am not going to get into what i belive on the red and green.

I go with what toyota sells to keep my toyota running like a toyota, others say the other stuff works fine.

Just type in coolant in the search and you will have more than 30 pages of posts to read which are quite interesting and redundant.

[steviej]

sk, I respect your thoughts on the red and the green.

However, I do not believe coolant color is the issue here. Regardless of the coolant color, the coolant is not staying in the cooling system. There is some mechanical reason (not chemical) that is forcing the coolant out of the cooling system.

In addition to having the cylinders pressure tested, have the cooling system pressure tested. It only takes a few minutes more.

There is a restriction in the system somewhere. The coolant expands somewhat as it gets hot, hence the hot and cold marks on the coolant overflow bottle. As your engine gets hot, the coolant should flow freely and thus be maintained at a steady temp. I'm guessing you got a blockage or partial blockage somewhere so when expanding, the easiest place for the coolant to go is out the overflow jug.

What is the temp gauge reading when the overflow happens? Why do you say it is not overheating.....is the coolant that flows out warm and not boiling? If you base this on your temp gauge, maybe you have a faulty coolant temperature sensor so the temp gauge reading is not true.

bear with me, I and thinking out loud.

sj

[SKperformance]

I never said the type was his problem ,his rad cap is ,but his coolant now looks to him like it is shot from the build up.

[steviej]

first problem is get the right coolant in their

I guess this mislead me.

sorry.

[SKperformance]

It should as reading it myself i didn;t explain it clearly .