rxmpvibes

Hello everybody, I have a 2006 Lexus GS430 w/ 100k miles. I've been trying to solve my coolant issue for the longest and I've been doing research like crazy!!! The issue that I'm having is that coolant from the radiator is blowing back into the reservoir causing the reservoir to be overfilled and splattering all over the engine bay. Also, when this happens the fluid in the radiator drops significantly ( I have to keep dumping the lost coolant from the reservoir back into the radiator). Under normal driving the fluid wont blow over to the reservoir that much (just a little) but, when I drive long distances or if I floor it that is when the coolant from the radiator really pushes over into the reservoir. When the car cools, I find out that the coolant from the reservoir does not draw back into the radiator. (I'm guessing due to the air in the cooling system?)

Checklist on what has been done to the car:
- NEW Water Pump (Installed by Lexus)
- NEW Timing Belt (Installed by Lexus)
- NEW Thermostat (Installed by Lexus) (I also tested the thermostat in boiling water and it opened and closed)
- NEW Radiator (Installed by Lexus also was pressure tested and passed)
- NEW Radiator Cap (Genuine Toyota 1.1 bar)
- Coolant Flush (flushed radiator and engine block with water hose)
-Bled System with my Lisle Spill Free Funnel and Heater on MAX HOT Full blast! Heater is working good!
(Did this 3 times for 30 min+ to get rid off all the air bubbles)
- Performed a Block Test to see if any combustion gasses were in the cooling system, to determine if it was a blown/failing head gasket (passed)

I dont know what else to do at this point other then do a compression test and a leak down test. There is no coolant in the oil and no coolant leaks.
Car drives solid and strong!
Is there a bleeder valve on the GS430 somewhere or does it have a bleeder valve? Is it something I'm doing wrong? Any help will be grealty appreciated!!!

Gotcha350

Sounds to me like you have a combustion leak...if you used the listle funnel and have air getting back in the system it most likely is coming from that.

Has the car ever overheated?

warandcar

the lexus dealership doesn't know the answer to this issue when the above items were done?>

rxmpvibes

Understood. Now, if it was a combustion leak, when I did the block test then how come the fluid stayed blue and didnt change color? Yes, the previous owner did overheat the car. However, when I went to Lexus, they had it in their service notes it stated that the previous owner did mention the car overheating. Lexus took the car in the shop to do an inspection/tests of the engine and everything was ok.

Now, with me the car did over heat 1 time but, I did not let it get to the red mark. I immediatley turned off the engine to get the car to cool. After a couple minutes I cranked up the car and the needle went down in the middle to normal operating temp. Right after, I drove home 10 miles with no issues( needle did not move passed the middle). Next morning, I checked the radiator and it was empty! There wasnt enough coolant to circulate the entire cooling system (this was when I started to figure out the issue with this car). Its been a coolant headache ever since.

Thanks!

rxmpvibes

Nope! After the mechanic at Lexus did the pressure test on the radiator and it passed I asked him if he thinks its a blown head gasket or any sign of a blown head gasket and he said no. He told me that he has an LS430 and these engines are bulletproof.

Gotcha350

Sounds like a headgasket issue to me...why it didn't turn blue...that's a good question...but now that the story is more complete...several overheating with aluminum heads and block usually will lead to some warpage...which is enough to cause head gasket issues. i'd get another test and a compression test

rxmpvibes

Ah man! I really hope its not a headgasket issue (thats the last thing I want)! A head gasket job for a GS430 can be anywhere from $3,000-$4,000!!!

How much do shops normally charge for a leak down test and a compression test?

Also, what should the PSI be for each cylinder when doing a compression test?

rxmpvibes

I will be performing a compression test myself. Once I do that then I will come back and give you all the #'s on each cylinder. I'll keep you all in the loop!

SILENTM

Compression should be above 190psi with a difference between cylinders less then 14psi.

rxmpvibes

Ok, awesome! Thank you very much! I'll keep a note of this.

warandcar

this is an interesting issue… can't wait for the outcome and hope for the best for you!

XxGoKoUxX

Only two things left, blocked coolant passages and faulty head gasket.

I pray it's #1 for you though. GL!

Here's a reference to people saying block tests are never a 100% positive test.

http://www.bimmerforums.com/forum/sh...ms-only-65k-(-)

EDIT: I forgot to mention, while you're getting it replaced, might want to look and see if this company or any other company sells performance head gaskets? They may turn out to be more bulletproof from overheating than your OEM head gasket.

http://ttcperformanceproducts.com/gs300400430.html

rxmpvibes

I know! I hope its # 1!

Speaking of blocked coolant passages...you know whats funny?? When I gave the car a coolant flush( ran a water hose through the engine block and radiator), when I went to refill the car with 50/50 antifreeze it only took a gallon. (this included bleeding the system with my lisle spill free funnel)? Does the entire cooling system for the 2006 GS430 only take a gallon to refill?

Thanks for the link and advice!

rxmpvibes

Thank you! I'll be sure to keep you updated.

XxGoKoUxX

Granted this is probably a older model GS430, I believe coolant capacity still applies since they're the same engine:

http://drivers.lexus.com/t3Portal/do...9U/pdf/6-2.pdf

If your lazy, it's supposedly 10.1L, or 2.66gal.

Hope it helps