Coolant High to Low every 1k Miles (1 Viewer)

[carlos33018]

Hi everyone,

I have been noticing that my coolant has been slowly decreasing over time at the rate of H to L on the overflow tank every 1k miles. The GX is a 2010 and has had the radiator replaced but looking through the service records it looks like the original water pump and thermostat are still in there at 150k miles.

Things Ive checked:
Front Skid Plate / Frame directly under water pump - No Pink Stains
Top side looking down into the water pump is hard to see but I could not see any pink stains either
Transmission Pendulum area from the underneath - Ive heard that this could have coolant if the valley plate is leaking - no leaks

The radiator that was used during the replacement is NOT OEM and the cap is also NOT OEM. I went ahead and ordered an OEM radiator cap to see if this makes any difference.

I am planning to replace the water pump and thermostat my self in the next few months. Any ideas on this ?


Thanks,

 

[r2m]

This may be a stupid question, but I'll ask it anyways. Are you getting any type of white smoke, either a little or a lot from your tail pipe?
If so, then you're burning some coolant, not good news...

 

[carlos33018]

This may be a stupid question, but I'll ask it anyways. Are you getting any type of white smoke, either a little or a lot from your tail pipe?
If so, then you're burning some coolant, not good news...

I don't see any white smoke coming from the tail pipe, looking around it doesn't seem like a blown head gasket is a super common issue on these engines. It can happen but so far I've found like 2 cases.

 

[carlos33018]

Also the color of the coolant is completely pink, no oil contamination etc. I have thought about performing a pressure test while engine is cold however this would not open the thermostat so I would only be pressure testing the radiator and hoses up to the thermostat.

 

[Acrad]

I'd replace your cap, if still having issues have a pressure test done on coolant system. This should quickly tell you if you are having an issue.

I've heard of small coolant valley that can evaporate before draining off the rear. Some coolant valley leaks can be seen via cheap USB borescope.

Post #41 on CL - coolant valley plate leak - ClubLexus - Lexus Forum Discussion - https://www.clublexus.com/forums/gx-2nd-gen-2010-present/850720-coolant-valley-plate-leak-5.html#post10922223

 

[jmanscotch]

High to low mark every 1K is decently fast, enough so that I’d definitely think you’d find some evidence of a leak.

If it were mine, I’d replace the cap (since that’s easy and cheap) but also do due diligence to look closer in all the concern areas: hose ends, radiator sides, below water pump (mirror on a stick device is useful) and the top-backside of the engine. If nothing becomes clear, then the pressure test idea definitely.

 

[carlos33018]

What’s the best way to spot a leak around the water pump area ? My pump is at 150k miles and I Want to eliminate this as a possible cause .

 

[Acrad]

You will see the pink cotton candy and stains either on the water pump or it will begin to drop down onto the skid plate and you will see during an oil change.

 

[carlos33018]

One things I noticed is that a lot of the compression clams (OEM) that were originally on the car were replaced by screw clamps. This was done on all hoses that lead in and out of the radiator. Are these types of clamps known to leak ?

Thanks

 

[Acrad]

I didn't realize myself until the last few years that the compression clamps are a lot better. Apparently they can more evenly distribute tension over varying temperatures. Screw clamps do not over the temperature range.

 

[carlos33018]

So I got myself a telescoping mirror and took a close look at areas around the water pump and thermostat and it does not look like there is any leak. I could not find any signs of pink cotton candy anywhere.

Now I did see that the color of the coolant in the reservoir tank and in the radiator we’re really different. In the reservoir tank everything looked pink / red as you would expect, but in the radiator the coolant had a brownish color:

View attachment 2564526

View attachment 2564527

 

[xychromosome]

@Carlos, check out my post here about the coolant color: Coolant paranoia - ClubLexus - Lexus Forum Discussion - https://www.clublexus.com/forums/gx-2nd-gen-2010-present/959055-coolant-paranoia.html
I had a similar issue and the color in the radiator looks that way due to the black background. If you take some out it should be same color as what is in your reservoir.

 

[carlos33018]

@Carlos, check out my post here about the coolant color: Coolant paranoia - ClubLexus - Lexus Forum Discussion - https://www.clublexus.com/forums/gx-2nd-gen-2010-present/959055-coolant-paranoia.html
I had a similar issue and the color in the radiator looks that way due to the black background. If you take some out it should be same color as what is in your reservoir.

Well you're absolutely right. I went to the truck, removed a small amount from the radiator and 100% pink, just like the coolant reservoir. Thanks for the tip .

 

[carlos33018]

Well the mystery of where in the world is Carlos' coolant continues. The water pump and thermostat have never been replaced on the truck and although they do not show any signs of leakage (confirmed by my fancy telescoping mirror) they are probably due to be changed out (truck has 154k miles on it.