Coolant Reservoir Bubbling and Filling Up.

Glad to have assisted getting you pointed in the right direction.

 

Older thread I know- but OP, is your truck still running good? Do you wish you had just replaced the whole motor with a lower mileage one?

I have 205k on my truck, and got bubbles in my overflow as of today... Looking at what the my options are...

Any pointers or gotchas you would share with someone following in your footsteps?

 

What Jimmy said,you can do all the tests you want,but the fact is you have a blown head gasket,a $3,000 fix.

 

The OP hasn't been around for almost a year, so not likely you'll get an answer.

Personally, my opinion is if the motor has over 200K miles on it, it's not worth cracking open. Find a 60K mile motor in the wrecking yard and drop it in.

 

That's kind of what I'm thinking too... Darn it!

 

A weak radiator cap can let pressure out too easily,the reservoir will fill too fast and bubble. Try a new cap

 

I would certainly replace the head gaskets on a 205K motor if I was familiar with the engines maintenance and use history. What are the compression numbers? (obviously one or more cylinders won't be accurate but it will give you a general idea). Has it been taken care of? Oil changes done regularly, etc.? 'Low mileage' motors don't mean much to me without a history or some pre-purchase mechanical testing. Common sense is a good guide here.

 

Didn’t even think of that… I’ll give that a shot! That would be awesome!

I agree with you… Unfortunately, I don’t really know the history of this motor. I’ve only had it for about 1500 miles, but it seems to run really good, and my last several tanks I’ve been getting about 17 MPG‘s, and it doesn’t feel weak. This is my third Tacoma, so I’m a little familiar with what they should feel like.

If the radiator cap doesn’t fix it, I’ll run a compression test before I buy another motor. Just to see what the numbers are. Then go from there.

 

a higher pressure cap isn't going to help since the engine can develop 200+ PSI when running

2005-2006 have been known to have leaking HG

Bubbles most of the time in coolant is head gasket, cracked head or block

Sorry but there is no easy button to fix this

 

200 psi!! You mean when a headgasket problem is present I hope.

200 psi would blast hoses apart and crack every plastic component in the cooling system!

He doesn't know if he has a headgasket problem yet, hence the recommendation to simply try a new cap first

 

Yes that s what I mean. Combustion pressures are nothing to sneeze at.
Yes 200 would burst things but that wont happen if the cap will release pressure below it

 

I'm not sneezing at combustion pressures. Yes it's probably a headgasket failure.. but what if it's not? A 15 dollar rad cap would be worth it just to be sure before he pulls the trigger on a head job or maybe gets rid of the truck.

After all, he is using the internet to diagnose a problem

 

Also a compression test won't tell you anything. You need to do a leakdown test.

 

I figured it would likely tell me what cylinders the gasket is shot between, and also some kind of idea what kind of shape the rest of the motor is in... Which would help me decide whether to replace the head gaskets or swap the motor.

I'm really not trying to diagnose over the internet... I figured what it likely was as soon
As I saw the bubbles.

I haven't had a chance to pull out my hydrocarbon test kit yet... Maybe tonight..

 

A compression test just isn't very accurate. The motor has to be in poor shape to get bad compression test readings and would never rely on it to diag the condition of the motor. Using a leak down tester will pump air in the cylinder which can reveal small head gasket leaks that a compression test would miss.

 

Don’t disagree. I just happen to have a compression tester in my toolbox and not a leak down tester.

I need to add that to my collection at some point!

 

Easy, got an auto parts store, buy an adapter to connect a shop air compressor to spark plug hole. Pull plug on cyl 6, connect air compressor, turn on air compressor, turn crank to close valves, what coolant bubble.

Or buy a $20 USB endoscope on eBay, pull plugs, put Cam in holes, cyl 6 piston will look clean, the rest have carbon build up.

Coolant pressure test WILL NOT diag head gasket failure in 1GR-FE.

This is what is happening.

Small amounts of exhaust gases are dealing into the coolant system. When you run tests
You are burping the coolant system. Removing the air bubbles.

It's a hairline crack in head gasket, a well known factory defect.

It takes about 2-3 days of normal driving for enough gases to get into the coolant system to cause over heating.

Now... On the highway, at highway speed, the air flow is keeping the engine cool enough to not over heat. Once you exit the highway, the airflow stops, you have a few minutes before over heat.

Trust me, head gasket us bad. If you need help with further diag let me know.

 

Nope! Not on 2004-2006 manufactured 1GR-FE, coolant pressure test WILL NOT push coolant into the cyl! This is first hand real world, doing the tests myself. You have to pressurize the cylinder, air will escape into coolant.

 

Compression test, again, not going to show bad head gasket, mine tested 180 on all six cylinders on dry compression test.

 

Next time you have bubbles or over heat. Let it sit overbight. when you start it, have someone listen under the glove box for a water rushing sound.