Ok my car has 259k mi. and it's overheating.

Here's what I've done:
Radiator, thermostat, timing belt, and water pump all done about 4 years (50k mi) ago.

Serpentine belt and fan clutch done earlier this year.

The two fans on either side of the radiator turn on when a/c is on.

There are no symptoms other than no heat until I turn it off and turn it back on, and the overheating.

The GS runs perfectly, no idling issues, no bogs, no smoke, or hiccups.

The first time it overheated I was taking a pretty steep drive up the mountains and I had the A/C on low (it fogs my windows if its not on.) Then I noticed the temperature gauge going up. Since there was no shoulder I blasted the heater turned off A/C and finally got to a place where I could pull over. I popped the hood and it was throwing coolant and vapor. It even cracked my expansion tank which was in really bad condition to begin with.

When I got it back home I realized the fan clutch was bad so I had it replaced. It was fine for a couple weeks under 20 minute drives. Then I took it out with the A/C on a warm day and in about 20 minutes it started overheating I immediately pulled over let it cool added water then drove it back home.

This is where I'm at now. My questions:

#1 Are the two fans on either side of the radiator only supposed to turn on with the A/C?

#2 Can the thermostat go bad so soon?

#3 Can it be a blown head gasket with not many of the symptoms?

#4 Upon searching here on the threads someone mentioned the harmonic balancer maybe not turning the water-pump fast enough?

Any help will be greatly appreciated.

 

check ur radiator cap, do the fans go on high with the ac on?

 

It doesn't hiss or evaporate coolant at the cap. And do the fans work at different speeds? I thought they just came on and off when needed.

 

To my knowlege the big Fan should always be on and increase speed as the RPMs increase and then go on "high" when the AC is activated. as stated above though change your radiator cap and see if that makes a difference. also let the car cool down overnight and in the morning remove the oil cap and look under it to see if there is milky pasty residue that looks like this.



which means that there is coolant in your oil which would be a blown head gasket

 

1) Yes the thermostat can go bad that soon. aftermarket thermostats can have different designs that will still work just fine(2 springs versus stock single spring..and in some cases vice versa), supposedly over time is where the difference between the 2 can be seen. There is no official proof or testing that I have seen on this, just conversations with radiator specialists.

have you tested your thermostat? if not take it out and put it in a boiling pot of water and use a thermometer to determine at what temperature it opens(match this with what the thermostat temp is rated at...also if you got to this point it can't hurt to but another thermostat and have it put in anyhow). if it does not open or locks at partially open then it is bad, and is not letting the proper coolant flow go through.

Yes you could use an aftermarket thermostat. it will work. pick which ever temp range thermostat you want. lower temp is supposed to keep the engine a tad cooler, but gas mileage will suffer a tad bit(Other than @ cold start up, I wouldn't really worry about this too much)


2) the big puller fan is supposed to turn with a very strong amount of torque. I dont know the exact way to test,[I don't advocate this at all as it is very dangerous and reckless] but i used my finger just barely even touching it and I was able to somewhat create a resistance against the fan moving. If it was working properly, this definitely should not have been the case. After I changed the faulty fan clutch, I knew it was working properly because every time I start it now, the fan roars for a good 30 seconds or more(never know because I start to drive)

For me I inherited this problem when I purchased the car 2-3 years ago. This faulty fan clutch led to an over heated motor a few times which led to a (possibly existing)blown head gasket.

3) To check for a blown head gasket go here:

Read Post # 28
https://www.clublexus.com/forums/gs-...coolant-2.html



4) If it was the harmonic balancer not turning the water pump fast enough then there is a good chance your alternator is not charging the battery as well either as they are all driven off of the same system. I personally don't think this is the case as you would very likely have battery/starting issues after a while.(I'm sure the battery light would come on)




Hope this helps

 

Thanks for the informative replies. By fans I meant the small and medium electric fans, not the big fan with the clutch that I replaced. Aren't those supposed to be like backup for the big one or are they both for the A/C compressor?

There is no residue like that at all aristoman.

kene I do get bubbles when I do the test in post #28 but I have no other symptoms of a bhg (no white smoke, no milky look in the oil cap, runs and idles great) so I'm praying that it's my thermostat which I am not too confident in removing to test in boiling water, as i don't even know where it is.

If it is a BHG does this stuff called steel seal work?
http://www.youtube.com/watch?v=3suQy...feature=relmfu

 

in some cases possibly, In my opinion the blue devil(aka sodium silicate... much cheaper online) will work better. But if you can replace the head gasket...I see your in cali. Im hoping so cal cause I know of a guy that did mine for 581$ labor, and also replaced the power steering pump for a total of 741$.


the bubble may be exhaust gases leaching into the coolant system through a missing piece of the headgasket. if it doesn't stop after about 30-40 seconds you may be in the market for a new head gasket. constantly overheating can lead to other issues if it doesn't get resolved.

where in cali are you?
let me know if you need that mechanic info or if you need me to go with you...hes in san bernardino.

let me know



If you can afford the possible~620$ for a new head gasket, new timing belt, new serpentine belt, new water pump, and new power steering pump(this is only labor of course) then I'd go for it and stay away from the sodium silicate.
If you are on hard times (like many are) then that might be an option.

 

i am assuming you completely burped the system of air, if not, then an air pocket in front of your t-stat could also prevent the coolant from getting to it and sensing the temp for it to open... try reburping the system first since this won't cost you any money...

then i would check the t-stat, i had a brand new oem one stick open after only a few months after installing it so the engine would take forever to warm up... so there are always possibility of defects and maybe it is stuck closed...

if everything is burped, the t-stat is fine and you are still witnessing fine bubbles, it is possible you have a seeping head gasket... get a compression test done...

 

Thanks again for the replies guys. I really appreciate the help I am getting. I am going to go ahead and check the thermostat before trying the blue devil as I am on a strict budget right now.

So it's near the block where the lower radiator hose goes in?

BTW I am in so cal in Ontario to be exact near off the 10.

 

cool.. im not far off from ya.

keep us posted if it gets fixed. Just giving you a head up beforehand. If the the coolant reservoir bubbles over now, and if the same issue happens with the blue devil in the system, it can get a bit messy near that coolant reservoir pressure release tube(pointing downward off of the coolant reserv. cap).

its similar to "lime scale" or hard water running through your shower head for the last year. It can be removed with out too much of a problem, just a little wiping. Mind you this will happen if you are still severely overheating with Blue Devil sealant in the coolant system. Remember blue devil is only supposed to be a temporary fix, although many have had such great results they just keep it in the motor.

It worked well enough for me so as I could use my DD while preparing for a headgasket change. to each their own.

Just giving you the heads up, cause some people are meticulously spotless when it comes to their engine bays.

 

Hey Kene where do you stay at? San Berdoo?

Alright I replaced the thermostat even though it seemed to be working because it would open when placed in boiling water and close after I took it out.

I replaced it anyway and I bought a radiator cap but it didn't fit. It is slightly smaller than mine.

How do I get the right size radiator cap? It isn't an OEM radiator, and I don't know which brand it is.

Anyways I was shooting some video to post here to see if it would help diagnose, and I found a cracked hose that was leaking water.

I don't know what it is called but it's located under the top radiator hose where it connects to the block, it looks like it goes from there to maybe the back of the block.

Is it an inlet heater hose?

How difficult is it to replace?

Anyways heres a vid of the hose I'm talking about, sorry about the mumbling.
http://www.youtube.com/watch?v=nTyyUil7Rrk

 

Here's a longer video. LOL at the pincher bug that comes out of the radiator while I was topping it off. Wish I had a program to trim down the vid to half the time. I am sure I didn't do something right to burp the system but I am just not too familiar with this type of stuff.

http://www.youtube.com/watch?v=vYmLKjb-qrw

 

I'm actually over here in the montclair region and I think that leaking hose is the coolant bypass hose that leads to the throttle body and back out.

 

did u ever find out whats the issue? im going thru the same ish.......so far, i noticed the 2 little fans r not spinning, the AC blowing hot air, when it overheats, alot of steam comes out the hood/radiator cap, the reservoir is still full, no bubbling, and im leaking coolant.......i burp it, only thing next is to try 2 get a new thermostat, and look for the leak?

 

Haven't found the issue yet, im a huge procrastinator. Hopefully I'll change the hose tomorrow and take it for a test drive.