Any help would be appreciated, I am at my wits end. I have an 07 RX350, a couple of months ago the temperature spiked to hot and I attributed it to a bad T-stat. So far I've had the T-sat and water pump replaced. I do not have a cooling issue...what I do have is missing coolant. I check the radiator after each use and the coolant is low as much as 16oz. The overflow seams to bubble after I shut the car off and there is a smell of hot coolant. I've had it to a reputable shop and they tell me all compression is good and I do not have a gasket issues. There is no coolant in the oil. The car runs great. Help!!!

 

The coolant has to be going somewhere. If it isn't going into the engine oil, it is leaking out somewhere else.

Toyota coolant leaves a crusty residue that ranges from faintly pink to reddish. If your reputable shop didn't find any sign of a leak (or overflow from the reservoir), one possibility might be a very fine crack somewhere that expands/opens when the system gets hot (and so leaks) and which closes up again after the system cools down.

You say you check the radiator after each use, and guessing that means after the car cools down, have you looked around under the hood right after shutting it off?

 

Unfortunately, when the car was overheating, there was a lot of blow off from the overflow and coolant went everywhere. I've tried to clean most of it up since and keep looking for any signs of a leak. Do you think a leak could be internal but not significant enough to blow out of the exhaust or go into the oil? Thanks for the help.

 

You said up to 16 oz coolant loss, and coolant loss each time, which is likely to show up in your oil (or exhaust if burned thru there).

You also said no further overheating issue -- could the missing coolant still be coming out thru the reservoir?

 

Correct, it no longer overheats. It may be coming out of the cap overflow tube but I do not see signs of fluid anywhere.

 

Is it possible it was not correctly "burped" when initially refilled, and was just never full to start with? I.e., adding to the overflow tank is not same as adding, burping etc to the radiator filler cap, which when I did mine, took a long time to get air out, squeezing tubes, running then stopping engine etc.

 

I had that exact conversation with the shop that did the work and they did tell me it could be a long process but they did not elaborate. Is there somewhere I could find out what the process is and the steps it would take? Thanks for your help

 

 

Steps from service manual, key is to fill it at radiator filler neck on driver's side, be careful, that is the hot part...

1) Loosen upper drain plug
2) Put a clear vinyl tube on vent plug located on upper drain plug
3) Fill radiator at filler neck (not overflow tank) until vent tube full
4) Install radiator cap, tight
5) Fill reservoir overflow tank
6) Warm up engine and while it is running squeeze the inlet and outlet radiator hoses by hand several times
7) Stop engine and let it cool
8) Remove radiator cap and check for fluid level in radiator
9) If coolant inside radiator (not overflow tank) is not to full mark, repeat steps 1-8 until it is
10) Top off reservoir tank if needed.

 

Looks like I have some work to do. Thanks for the input.

 

It is good practice to check your fluids periodically. Oil-Trans-Coolant-Brake-Power Steering, top off as needed. Also important to keep track of the mileage so you can easily determine when fluids need to be changed per manufacturer’s recommendation.