LegendaryJ

First and foremost, thank you for reading this past, any and all help is greatly appreciated and valued. This is my first thread.
This is also my first Lexus [1999 GS300] and first car I've done more to than changed the oil on.
My issue is my engine is overheating and there's no hot air blowing thru the vents, only cold air. I've changed the thermostat and put stop leak in - I was losing coolant rapidly. Now I'm not but the car's still overheating. I need experienced owners ideas of what's not working. I'm just beginning to work on my car myself with a few mechanics for guidance and assistance so getting things done won't be a problem but their opinions are all confusing me since stop leak and thermostat haven't fixed it.
Please and Thank you for the help.

Extra maybe good info to know?:
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I got it from an auction and it didn't make it home. Thought it was alternator turned out to be fuel pump (now when 1st start of the day, it takes a minute before it pulls off in drive but is immediate in reverse but that's for a different thread) changed both to new. Drove it for about two days before I noticed I was overheating. Once it overheated too the point the temp went over all the way and then back down to as if it were off. The vsc on and off lights are on. Check engine is on but I haven't gotten it to anyplace with a reader to say for what yet. I Added water after cooling but it was a constant drain. I put stop leak -Bars- stopped the leak but not overheating. Was instructed to change thermostat. Didn't change anything after.
thanks again.

firelizard

iTrader: (1)

Find the leaky part and replace it. Anything that has coolant in it can leak, so check them all.
Clean everything up while it's empty of coolant and when you fill it back up, look at where coolant is leaking from.

If you drove the car without coolant to the point of overheating and beyond, there's also a chance you've permanently cooked it.

LegendaryJ

Thank you so much for your reply.
I just ordered a water pump last night and the radiator doesn't seem to be leaking. It's been leaking from by the engine and none by the radiator itself. I've noticed the normal fan doesn't turn on but the AC on fan does. How do I check if that's contributing and if so possibly where would I find out from?

firelizard

iTrader: (1)

Your fans are not contributing to your coolant leak.

LegendaryJ

thanks again for your reply.
I thought it may be contributing to the overheating. Are there any places I should look for fuses or something to rule the fans out? After some reading I found that a water pump fixed similar issues but I just want to cover as many angles as possible.

firelizard

iTrader: (1)

If coolant is pouring out of your motor, the problem isn't your fans. Stop trying to guess randomly and find the leak. Odds are the fan doesn't turn on because the temp sensor doesn't have hot coolant passing over it to trigger the fan.

lexo98

iTrader: (2)

sbagdon

If you aren't leaving puddles, then it sounds that the coolant is being consumed by the engine... bad head gasket? If you bought it at auction, that might be why it was at auction.

As per no heat and overheating, and there's no coolant consumption by the engine head, and there's no puddles, I'd guess thermostat stuck open. Try replacing the thermostat, burping out the air, and then checking.

We had a mini-van with dual-zone heating/cooling, and that was our problem... no one had ever "burped" the coolant lines from the highest point in the system. Once the air was out, engine ran at normal temp, and heat blew hot (opposite issue then yours, the system was running cool, yet air bubbles and the thermostat can work either way).

firelizard

iTrader: (1)

Dude. They already said that it was leaking coolant and that they've replaced the thermostat. Whatever the Stop Leak plugged is still broken.

sbagdon

It would be best to know where the coolant leak was.

Plugged is "still broken"...?

firelizard

iTrader: (1)

Yes. StopLeak is a temporary solution. Frankly it's not even a good one because you shouldn't be introducing anything into your cooling system other than water or the correct anti-freeze.

The only way to properly fix a coolant leak is to replace the leaking part, see my previous posts.

LegendaryJ

Thank you all for replying. I was away but I'm back and I started her up. No fluids in the radiator but the reservoir is normal. I don't see any leaks. Car didn't overheat but I barely ran the engine from past results. I'm letting the engine cool with the hood up as I write this but I just got a water pump in the mail since that's what I was told by a mechanic who's seen it. Hardly believe it's a head gasket as I've also received it's not from other mechanics but I'm trying to follow directions. I don't know how to burp it. Is it car tilted up? But then still no heat. I'm confusing myself. Just gonna change the water pump with hopes it fixes everything.

firelizard

iTrader: (1)

Pick up a timing belt and change that while you're in there, if it hasn't been done in a while. You have to remove it to replace the water pump anyways. "Burping" is just bleeding air pockets out of the cooling system. Air doesn't transfer heat as effectively as water, so air pockets in the cooling system reduce the cooling capacity. The are ways to force-fill the cooling system so it doesn't need to be burped afterwards, but if you are refilling your coolant at home, yes, you'll want to make the filler the highest point so that bubbles will rise to it and escape.

If you were losing coolant via a split head gasket it would be ending up in your engine oil, which would look like chocolate milk afterwards. Coolant leaking into the cylinders would also smoke a lot.

LegendaryJ

Already got it halfway off, too late for timing belt too but afterwards I can grab one and do this part of the job again. I'm crossing fingers. Does look like chocolate milk a little on the bottom of the oil pan but I'm thinking cause there's a lot of oil residue around the pan. Kinda normal looking as I just checked another car on a lift.
Thanks for clearing up a burped air way.

LegendaryJ

Ok so here's where I'm at. Got everything except what I'm thinking is a tensioner and the timing belt left to pull off. There's a hose on the water pump that's still dripping. Is that normal? How do I not throw off the timing and can it be re-established afterwards without another trip to AutoZone which I won't have until tomorrow if I'm not driving there in my 300?