Possible reasons for leaking heater core

AUSVX · #1 05-06-2009, 03:17 AM

Hey all

Looks like I caught it in time because it doesn't seem too bad, although I haven't taken off the carpet yet.

I don't want to fix the problem until I know the causes so it'd be great if anyone could chime in giving any ideas of what it could be.

It gets pretty hot in the foot well on the drivers side and when the car is fully warmed up, with the centre console off, I've realised that the metal all around that area is pretty dam hot. The transmission seems as though it's on it's way out, and I'm not sure if it's hooked up to the radiator (PWR). Was just interested to see if anyone thinks that the heat that MIGHT be coming from the transmission area is creating extremely hot coolant when it runs back to the radiator??? Possilby causing the heater core failure?

Any other ideas would be great

Thanks, Jordan.

dcarrb · #2 05-06-2009, 04:52 AM

Heater core failure=coolant leaking onto floorboards.

Have you modified the exhaust or removed heat shields?

What makes you think the transmission's "on its way out?" If the transmission cooling lines were not connected to the radiator, you wouldn't get far.

dcb

BRADY · #3 05-06-2009, 06:40 AM

Hi Jordan.

Have you spoken to the auto transmission guy in Newcastle yet? He may have some answers.

Hope to see you soon and go for a ride in my fully functioning SVX. (Please God, let my SVX behave.....)

Rock on.

IceBlade · #4 05-06-2009, 08:04 AM

I have the same problem with heat. I dunno what it is or what to do about it.

AUSVX · #5 05-07-2009, 01:52 AM

Unfortunately I know heater core = leaking onto floor boards, very frustrating.

What I was saying was, if an overheating tranny was passing very hot coolant on it's way back from the tranny and circulating through the system, do you think it's possible that could blow the heatercore.

Thanks for the contact Brady, no I haven't spoken to the tranny people yet but thanks for the contact.

Tranny used to slip from 2nd to 3rd occasionally, now it does it all the time and has it's clunks and shudders plus a 1/4 of the fluid that I would pinch off the dipstick with my fingers would be black.

If you're suggesting that removed heat shields have anything to do with the heat around the foot well and centre console, please explain, I've already thought about that but don't have a hoist to check. From a diagram that I've looked at, from memory the SVX also has a massive tranny shield between the tranny and underbody hopefully some idiot hasn't taken that off.
BUT if you're suggesting that removed heatshields are related to a leaking heater core please explain.

dcarrb · #6 05-07-2009, 05:24 AM

(Be advised Im no expert.) Missing heat shields and/or a modified exhaust could possibly explain the excessive heat from the console, but would have nothing to do with a leaking heater core. Conversely, I cant see how a bad heater core could cause excessive heat from the console area. An overheated transmission shouldnt over-burden the cooling system. My guess is the heater core is failing from age-induced corrosion, and the heat issue has to do with the exhaust/heat shielding. Failing transmission is an unrelated problem.

dcb

svxistentialist · #7 05-07-2009, 07:22 AM

Jordan

In your description you mention a number of different symptoms. These may be unrelated to your heater core problem, and as such just add confusion to troubleshooting your problem.

Regards the heat shield under the console being missing, I doubt this is the case. It does not have to be de-mounted to work on the transmission, is not in the way of anything, so nobody would have a good reason for removing it.

In normal circumstances the auto transmission runs very hot. It's hot enough to require the heat shield to minimise heat leakage into the cabin. In your case it is bound to be worse. When your transmission is failing there is extra slippage, which causes more heat build up, which radiates into the cabin via the console area.

In addition to this you are mentioning black fluid on the dipstick. It's the job of the transmission fluid to conduct heat out of the transmission and "lose" it via the radiator/cooler externally. When the oil breaks down it no longer does this job effectively, and this is why transmissions fail, the clutches get burnt up by too much heat.

Long story short, you will be experiencing significant extra heat from the console area because the trans is failing.

dcb is correct I would think. Your coolant leakage into the car is most likely caused by corrosion in the heater matrix or the pipes inside. You would need to attend to it quickly, losing coolant is bad news. Unfortunately you will have to strip out the dashboard to get at it. There is great information in the How To section on the aircon system AIRCON. Read through this, it will give you an idea what to expect round about pps 21-24.

Joe

svxistentialist · #8 05-07-2009, 07:29 AM

PS:

Your transmission must be connected to the cooler in the radiator, or to some other external oil cooler, otherwise your transmission will continue to burn up.

Just out of interest I was looking at this heat leakage into the cabin from the transmission last summer, because my aircon had leaked away the gas and was not cooling. A serious amount of heat gets into the cabin.

There is no airflow across the top of the transmission that might take some of the heat away. I'm wondering if there is an easy way to run a duct from a high-pressure area up front to the top of the transmission, that would force cooling air across it? That would be a nice mod, which would then allow the aircon to cool the interior a lot better. [Because it would not have so much heat to get rid of]

Joe

AUSVX · #9 05-08-2009, 05:08 AM

Yeah the air must really struggle to get to the top part of the transmission, I can't think of anything quick and easy to throw some air in there.

Yeah this heater core is a big job, luckily I got it before it got too bad, it hasn't leaked too much, and the ABS unit is ok.

Unfortunately there are 3 big jobs involved. rip out all interior, rip out dash, and rip out heater core.

So far the heater core has been bypassed for the time being, the seats are out (no broken bolts). I'm up to the carpet where the rear seat connects to the 2 black plastic pulling things, you pull on them and the seat pops up.
I can't disconnect those plastic pieces from the body of the car.
Any suggestions???

Jordan.

AUSVX · #10 05-09-2009, 06:07 PM

Ok, so I'm up to the dash now. All seats gone, all carpet gone, abs outa there.

Does anyone know whether to take off the dash from drivers side all the way to the passengers side to get to the heater core? or is there an easier way???????

Thanks, Jordan

immortal_suby · #11 05-10-2009, 10:10 AM

Quote:

Originally Posted by AUSVX

Ok, so I'm up to the dash now. All seats gone, all carpet gone, abs outa there.

Does anyone know whether to take off the dash from drivers side all the way to the passengers side to get to the heater core? or is there an easier way???????

Thanks, Jordan

There is no easy way.
You have to drop the steering column, remove the instrument cluster, remove the glovebox, remove the radio, and the whole dashboard is one huge piece. You have to pull the whole thing out the passenger side door. I removed the center console also, not sure if you could leave it in or not.

Then you have to unbolt the steering support bar. You can pull it back enough to get clearance to remove the heater core.

edit: just noticed you are down under. I did this on a USDM svx. Might be some differences that I don't know about.

AUSVX · #12 05-10-2009, 11:49 PM

I can imagine me having the whole length of the dash in both hands and seeing where my knees are that there are some electrical still connected to the dash. It'd be great if you could maybe list a few things that are connected to the dash.

I have taken out the instru cluster before but not sure if somethings connect to the dash and then to the instru cluster.

Yeah the good news is that the glovebox, centre console carpet, seats and other things are out.

Bad news is that I'm going to check the head gasket before I continue.

immortal_suby · #13 05-11-2009, 02:56 PM

There were 3 accessory plugs behind the parking light and mirror switches.
I don't remember what was behind the instrument cluster.
Once you remove the radio that takes all those wires out of the picture.
The manual button connecter for removing the shifter.

It's been almost a year, I don't remember everything.

Someone who's done it more recently could give you a better explanation.