xt1956

The other day I made a 20 mile trip and when I got home, the coolant in the reservoir was bubbling. The car was not overheating... gauge was at normal temp. I decided to change the thermostat and do a coolant flush. I am not a mechanic... have done a few minor maintenance items like changing oil, replace bulbs, replaced a belt once. I watched a YouTube video on changing coolant in a Lexus SC. I got Toyota Red long life coolant, distilled water, new OEM thermostat and a new radiator cap & bought a no-spill funnel kit. Drained the radiator and didn't see any oil in the coolant. I did the flush, and rinsed with distilled water 3 times to make sure I got it good and clean. I replaced the thermostat, added new coolant using the funnel kit. Let the car run with the reservoir cap on and the funnel still in the top of the radiator with the heat turned up. Got it up to temp and let the car run for about 20 minutes until there wasn't a single bubble in the fluid in the funnel and levels in funnel and reservoir were steady. Coolant in the reservoir was between min & max.

I put on the new radiator cap and drove 7 miles with the heat on. Came home and checked the coolant. Level in reservoir was the same, no bubbling, temperature gauge normal at halfway. Then I drove the same 7 miles with the air conditioner on. When I got back & turned the car off, I heard the bubbling sound. Temperature gauge good at halfway-not overheating, opened hood and coolant was almost to the very top of the reservoir! Once it was cooled down, the coolant level in the reservoir was back down, opened the radiator cap and fluid was down maybe a cup or so. The entire time I was doing the flush and while the car was running in the driveway there was no leaking on the ground from anywhere.

Not sure what's going on. why would the level of coolant fill up in the reservoir so high? I honestly don't usually check under the hood when I get done driving... the coolant in the reservoir isn't supposed to go way up like that, is it?

jimbosr1

coolant does raise in the expansion tank when driven but not to the top of the tank, however the bubbles are your problem.either you have air in the system or have a head gasket going bad.i had the exact issue with my 86 mr2 and it was the head gasket.
it will not over heat until your coolant flows out of your expansion tank and system gets low.dont drive it until you get it fixed.

Brennen01

When there is foam or bubbles that means that there is air trapped in the system somewhere. You will have to flush the cooling system, you'll squeeze the upper radiator hose with the car running and the heater on full blast with the cap off of the reservoir. I may be forgetting a step, I have not done it in quite a while, you can just YouTube how to get air out of your cooling system and there's a lot of how-to's on there.

Good Luck!!

eknine9

iTrader: (8)

Yes, bleed the system again with the heater on. I know coolant diverts when the heater is on and when it's off, so when you bleed it you need to do it with the heater on and with the heater off. You may have had air trapped in whatever the valve is called that controls the heat.

doodles714

iTrader: (1)

Make sure you have the correct radiator cap.

xt1956

I bought a new radiator cap, confident it's the right one - it fits well. So you are saying to bleed it with the heater on full blast and also squeezing the upper radiator hose.

1. Should I be doing this with the radiator cap on?

2. How long do I do this for? When do I know I am done bleeding it?

3. eknine9 - Are you saying I need to bleed it a second time by squeezing the hose while running the car with the heat off too? And again... How do I know when I am done bleeding it? When do I stop squeezing the hose?

eknine9

iTrader: (8)

Also make sure you have the front end higher than the rear when you bleed.
And yes, Leave the cap off while the car warms up with the funnel in. Run the heater on full blast. Squeezing the upper rad hose also helps as well.

I honestly can't tell you how to tell when you're done bleeding. When I last did mine I left it going for quite a while and kept squeezing the upper hose long after bubbles stopped coming up. I also switched it to Full AC once and went through the bleeding process again, but I don't think the AC is a necessary step, just the heater.

xt1956

ok, thanks for clarifying. When I did my coolant change, I did have the front end up on ramps. But the thing I didn't know about was squeezing the hose. It wasn't in the video I had watched with the no-spill funnell. Will try this again tomorrow and hopefully it will do the trick. Thanks again!

scsexy

iTrader: (1)

Could just have an air bubble in your heater core. Happened to me in my sc300 and i was hearing the same bubbling after a long drive. Heater worked fine. Mine started after i replaced the water pump.

Drive with the heater on full, Somewhere safe do some aggressive turning like your trying to shake any air bubbles into the passage ways from the top where they would be stuck.

xt1956

Thanks for the additional suggestion. Definitely wouldn't try it where there's traffic, but out here in the boonies I can probably try it out where there's little traveled road with no houses.

xt1956

Today I put the car up on the hill by my driveway about 45° angle or greater. Took off the reservoir cap, put the no-spill funnel in the radiator, and ran the car at over 2000 rpm with the heat blasting. Placed a cement block on the gas pedal. Ran the car for 30 minutes and still had small bubbles coming up in the funnel. An hour.... two hours... less bubbles but occasionally a few here & there. The coolant in the reservoir stayed at the same level the entire time and so did the level of the coolant in the funnel. Temperature gauge showing normal-right in the middle. Nothing dripping under the car. After 3 hours I turned the car off, capped the reservoir and removed the funnel and put the radiator cap on. Went for a drive with the a/c on medium. When I got back, I could hear gurgling in the reservoir. Opened the hood and the coolant was almost to the top of the reservoir. Temperature gauge still normal, not overheating.

So how does one for sure diagnose a head gasket going bad?

KahnBB6

iTrader: (5)

I have also recently been trying to determine if I have a head gasket that is beginning to go.

I've paid Blackstone to analyze my oil with some informative results but I am also tempted to try out one of these kits. I have no experience with using one but so far it does not seem to be bunk. Anyone care to comment on this if they have happened to use one?

The one used in this video is a U-View Hydro Carbon Radiator Leak Cooling System Tester (P/N 560000). It's $57 on Amazon.

I've also posted about this in my USDM GTE swap thread to get opinions before I commit to opening up my engine and spending a couple thousand.

xt1956

Something I probably should have mentioned. Three years ago the car was in a front end collision and the radiator was replaced. When I drained the coolant the other day, Orange coolant was in there. Could this have clogged up or damaged the radiator? Could that possibly cause the problem with bubbling in the reservoir but no overheating?

scsexy

iTrader: (1)

Sounds like they put stop leak and yeah that could be bad for the system. If they mixed green with red toyota stuff it would be more brown than orange. If you can rent a Coolant presure tester pressurerize it to 15psi and run the car. If you have a bad head gasket the pressure on the tester will rise as combustion leaks into the coolant system

xt1956

Not sure why anyone would put stop leak into a brand new radiator when installing it. It had the orange dexcool in it, not a mix of red & green. This shop made other obvious errors in their work I wont mention. Before I did this coolant flush, I googled what kind of coolant to put in the car and it said dexcool. And I read some other blogs that said it could do damage. I checked with the Lexus dealer before buying any coolant to make sure and put in the Toyota red long life. I was mentioning this in case anyone here had any experience with having had dexcool in their car.