BRZ overheating
 

hello all, i'm hoping someone can help. I had my brz parked for a year (license suspension) when i finally got it back i pulled my car out and there was a huge dried puddle of coolant i'm assuming. I went to a shop to have my oil changed, told them what was happening and see if they could diagnose the problem. They said I have a small coolant leak, they tested all my fans etc everything is fine. they said keep the coolant topped off and it should be fine. no auto shop can or is willing to get it on a car jack because i've lowered it. so i kept the coolant levels topped off and it's still overheating. so i thought it might be the thermostat. I took out the thermostat (which is a total bitch to get to) tested it and it's fine. resembled everything, cleaned my skid plate so i could see if there was additional leaking. filled it with subaru's special expensive blue coolant etc... just got back from driving it about 10 miles, overheating again. checked the skidplate and there is the blue coolant leaking on the driver side looks like it's right under the thermostat housing. super frustrating, hoping i can get some advise. hope it's not the head gasket :mad0259: thanks for any responses

have you checked the rubber hoses that lead to the radiator and engine for cracks?

i have, i did a flush, filled the radiator with water waited an hour too see if there was any leaks before i put the skidplate back on

$10 says it's a weeping waterpump

Man auto shops won't put your car on a lift cause it's lowered? That's obnoxious.

I would also guess the water pump is faulty. How many miles are on your BRZ? I feel like that could be a warranty issue.

Sent from my Nexus 6P using Tapatalk

How is the coolant overheating being diagnosed?

Could be air trapped in the system. May just need a better/more complete bleed...

-alex

My first supra would overheat and everything checked out perfect.
No leaks and system pressure tested fine.
Until we decided to replace the water pump just because it was the last thing that it could be.

The pump impeller was almost completely eroded away and nothing left but a nub.

It was from using the wrong coolant. It dissolved the impeller.

I think the new pumps have plastic or ceramic impellers, but I am not sure.
Either that or your system has an air bubble from the slow leak and you need to purge it.

Just having a slow leak (by itself) will not cause the car to overheat

Yeah it is obnoxious, Subaru won't even do it. around 30k hopefully it's just a water pump

maybe, but what would cause the leaking?

this could be it, I bought it used not from a subaru dealer. previous owner could have put wrong coolant in, it sat for a year and eventually dissolved something in the water pump????

thanks everyone for your replies, appreciate it... no one around here seems to know anything, including subaru

because nobody experienced like this or yet.
if everything checked fine, then water pump could be issue like someone said

FYI in the future I'd strongly urge not letting a car sit for an entire year unused. That's hell on the car. I understand your license was suspended but ask a friend to drive it around every once in a while (if that ever happens again).

I'd also recommend lifting the car a little bit; otherwise it sounds like no shop will ever work on your car in the future.

Wow... you didn't even wait for a reply.

Again: I ask why you think it's overheating. I am not speculating on leak source, I am asking why you think it's overheating and how it is diagnosed. If you can't describe how you reached the overheating conclusion, you aren't telling us the whole story and no one can help you, not even Subaru.

Leaks in the coolant system are from any of these sources:

- heater core
- radiator
- hoses
- leaking head gasket
- water pump
- radiator cap

Overheating is from any of the following:
- actual overheating
- air trapped in system
- bad radiator cap
- leaks
- faulty coolant temp sensors

If you are having an overheating issue but you can run the engine with no visible leaks, then you simply need to bleed the system better.

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-alex

Sorry, when i said "around here" i meant the auto shops in Boise, sorry for the misunderstanding. I appreciate everyone on this forum. I'm not sure what your asking about as far as diagnosis. other than it says it's running really hot. It redlined to "h" the other day and the check engine light came on, so i turned off the car and coasted the rest of the way home, obvious smell of coolant, hood is extremely hot to the touch after driving 5 miles etc... I did bleed the system, maybe I need to do it again/better, but that still doesn't solve the leaking problem.... it's leaking right around the thermostat housing which the waterpump is directly above it, so i'm thinking waterpump? all the hoses around there look good

it's funny, I wouldn't let anybody drive it, including my gf that lives with me because it is so damn low, if you don't take a speed bump at the wrong angle boom... and I have been looking into some spring rubbers to bump it back up around an inch

Lowered on springs?

yes

@Notso Rent a coolant pressure tester and take it up to 1.3bar, and start looking. Once the system is leak free, put the drivers side front up on a jack stand so the thermostat is at a higher point, run the car with the rad cap off and the tool Mav1178 suggested installed and filled with coolant, run it for about 20mins or until the lower rad hose is warm, turn on the heater full blast and let it run for another 30mins or longer. You should see bubbles, that's a good sign.

If you continue to drive the car in this fashion, you will need a new motor soon.

I ask about diagnosis because overheating is caused by simple things. I am assuming when the car was in storage, it was operated from time to time to keep things properly lubricated... we can assume the water pump is leaking from what you are saying, but if a qualified mechanic can't find a leak, then 1) they are giving you BS, or 2) you don't actually have a leak from the water pump.

At this point, your coolant system needs to be pressure tested before any other assumptions are made.

-alex

It hasn't been driven since i tested it with the thermostat being taken out. and a mechanic hasn't been able to find a leak, because no one is willing/able to get it on a car jack to look at it. thats why I came here, to gather info and do it myself, but i know there is a leak, i cleaned the skidplate before i put it back on. nothing leaks when it's sitting, but when i last drove it around the block there was blue coolant (not a lot) but some sitting on the skidplate just under the thermostat housing and water pump. I'll pressure test it when i get back in town on Monday. Whats the diagnosis if it's not up to preasure? the pump? Thanks again Alex, I appreciate your input

Pressure testing your system for a leak is not measuring pressure. It's introducing pressure to your coolant system to simulate the conditions under which it may leak (higher temps, coolant boiling over, air pockets, etc that add pressure to a closed cooling system)

You really should look up how this type of testing is done, there's plenty of documented sources online.

-alex

I think this is being made more complicated than it needs to be. If you know there's a leak, you already know that a pressure test is going to fail, because you have a leak. There's really no point in doing a pressure test when you can see the visual evidence of an active leak.

If you know you have a leak, the logical next step is to find the source of the leak. That involves a very special technique professionals call noggin pokin'. The way you do this is to poke your noggin in there and see with your own eyes what's happening. You already have a general idea of where the coolant is coming from, so you already know where to start pokin' your noggin.

The water pumps on most cars have a weep hole somewhere on the bottom side to allow coolant to escape when the water pump is failing. You'll probably have to look at it from underneath to see it, but you might also be able to get a mirror or inspection camera in there instead. That's where I would start. Even if it turns out not to be coming from the weep hole, you already need to poke your noggin in there to find that leak anyway.

Fix the obvious (the leak) first and see if that stops your overheating issue. If not, move on to the next potential cause.

A pressure test is to help you find the leak without having to get it to temperature to pressurize the system. It is harder to work on a hot engine and if you want to unhook a hose you will have to wait for it to cool all the way down. With a pressure tester you can pressurize/relieve as many times as you want without running the engine.

Are you going to stick your head down the front of a running FA20???
Oh wait what other way might you get the system pressurized other than running the engine?

The weep hole on a water pump will tell you when the shaft bearing/seal is failing. It will not tell you if it is pumping.

You can use your cellphone as an inspection camera and you can stick it in places you probably wouldnt put your head.
There are even apps where you can use one phone as a wifi camera and another for the display. Like a wireless inspection camera.

Ill throw another 10$ at the waterpump. Just what it sounds like to me if you "tested" the thermostat. For future though to save some money drain the system leave the thermostat out temporarily and run distilled water in it to save on the coolant money till you fix the problem. when its fixed throw everything back in how it should be. Just my opinion.

Part of the problem is that OP isn't diagnosing it properly. It obviously leaks when it's hot, but when it's just normal idle it doesn't.

Stupid mechanics don't help either.

right, which is why i came here, to figure out how to diagnose/fix it. a lot of people have mentioned a pressure test, just watched some videos on it and i should be able to find the leak under pressure. i'll report back my findings when it's done

BTW the stock radiator cap is 1.2 or 1.3 Bar. You should pressurize the system up to that point (or close) and it should be able to show leaking from wherever it may be.
Thermostat temp doesn't matter as the cooling system will be pressurized on both sides of the thermostat.

-alex

You don't have to pressurize the system. You can just look for dried coolant, because it's not invisible.

You can always go play tea with your dollies while it's cooling off.

No, but maybe you should. I would just do what I've done for the past 30 years, which is look for traces of the leak with the motor off. Because it's not invisible. And this is not nearly as complicated as you're trying to make it.

If there is coolant leaking from the weep hole, the water pump needs to be replaced. Period. Unless you're suggesting that he should ignore a leaking water pump, which would be unbelievably stupid. You're not suggesting something so unbelievably stupid are you?

Well, he has diagnosed that he has a leak, unless the coolant just magically appeared from a land where unicorns piss coolant into our dimension.

Is that obvious? How do you know? He doesn't know, because he hasn't looked.

Maybe I'm old school, but in 30 years I've never had to apply pressure to a cooling system to find a leak when I could see the coolant with my own eyes after just running the motor. Traces of the coolant are usually visible, and the expense and extra trouble of a pressure tester doesn't actually prevent you from having to poke your noggin in there and look for yourself. Diagnosing this is something he could go out and do right now if he wanted without having to do any extra research or buy any extra equipment.

It just really isn't that complicated.

you can add UV dye to your coolant might be easier to trace leak.
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i agree with alex said, there is a chance there are air trapped in the system cause over heating and cause over flow of coolant. but i would think very likely mouse chew a hole on your hose. btw, did you ever check the coolant line goes to the throttle body ?

So you are saying that professional mechanics are all just stupid. Got it

I wont candy coat it - F*&* you.
Because waiting ~1 hour between troubleshooting steps (heat up engine to pressurize, look for leaks wait for engine to cool before unhooking something) is FAR more efficient than being able to repeat troubleshooting steps in 3 minutes by repressurizing the system.

My POINT IS that with an old 57 chevy, you can almost climb IN the engine bay while it is running, but with this engine you CANNOT put your head in front of the engine even when it is NOT running.


My point was that the PUMP MIGHT STILL BE TOAST even IF the weep hole is dry.


Again - there is this professional technique that MECHANICS use called pressurizing the cooling system.
It is pretty much #3 in the cooling system troubleshooting steps after #1 Check your coolant level and #2 Look for a BIG LEAK.


The OP has already stated that he has a SMALL leak and cannot pinpoint it.
It is apparently easy to get your panties in a wad.

You can slam a car, but not diagnose an issue like this?


Also, if you seriously overheated the car a couple times I'd be looking in to more serious issues.

LOL. Let's start with this:

No he didn't. He said he hasn't raised his ridiculously lowered car up to a reasonable height to look for it yet. He was fishing for someone to tell him where it was likely to leak before actually poking his noggin under there to figure it out.

If he had already done that and couldn't find the leak, then it might make sense to pressurize the system. But when you haven't even done the basic visual inspection, jumping right to a pressure test is silly. And he's still going to have to raise the car up and still going to have to put his head up under there, even with the system under pressure. So all this does is make the visual inspection more complicated than it needs to be.

But you can raise the car up, remove the covers and look with your own eyes. You can also slip in a mirror or inspection camera, if you have one.

In your quest to make this easy diagnosis as complicated as possible, you're missing the simple fact that it isn't necessary to heat up and cool off the motor to poke your noggin under the car and visually inspect for leaks of not-invisible coolant.

A professional mechanic is not going to go to the trouble of pressurizing the system if he can see the leak without it. He'll do that if he can't find the leak, after poking his noggin in there. Then he'll pressurize the system after fixing the leak to make sure that was the only one.

And he's also not going to be frightened by a little warm coolant and run from the garage screaming for his mommy.

By the way, come to think of it, the last time I diagnosed a coolant issue on my Jeep, I couldn't quite see where the leak was coming from. So I put on a pair of safety glasses, started the Jeep and slid up under it to watch. Oh noes! So scary!

If he's too low to get it on the ramp style lift or to get the arms under it, it's his issue, not theirs.

BS. Cooling system works because it's pressurized. Lose the pressure and it causes localized boiling, massive over pressure, and very rapid overheating. Pinhole leak is all it takes to lose pressure.

umm yes I have, how do you think i got the thermostat out? the only way to it is underneath the car... and you don't think i was looking around everywhere down there to find the leak i'm so worried about? really?

Sorry about that. I thought in one of your posts you said you didn't want to jack it up until you knew where to look. Must've misread that part.

So a car's cooling system will not work when first started up because it is not under pressure.... got it.


He is overheating in just 10 miles. That is NOT due to ONLY a pinhole leak,
Like I said:

it could only be caused by a pinhole leak which caused another problem, like a bubble in the system.

Man, trollie is the gift that keeps on giving.

A car's cooling system does nothing when you first start the car because the thermostat is closed and coolant isn't moving.

My Point was that the system does not need to be pressurized before water starts moving through it.
If his car is overheating in 10 miles it is NOT because of a pinhole leak UNLESS the pinhole leak CAUSED A BUBBLE.
Which was precisely what I meant in my first post:
I guess that English reading comprehension is not your strong suit.

Did OP car ever get fixed?