Antifreeze IN my interior!!

[sothpaw]

Tonight was my first bizarre Corvette experience...

I was driving into a parking lot at low speed, when I hear a hissing sound. I can tell it's
coming from the car, so I shut her down. Even as I'm doing so, the windshield fogs over.
There is the smell of antifreeze about the cabin...

...it has drenched the passenger floor mat and floor! It is leaking under the car!

This reminded me of last week, before I went autocrossing, when I picked up my helmet from
the passenger floor, it looked like it had something wet on top. I was in a hurry and ignored
that...opps. But the floor mat looked clean.

The leak stopped in the parking lot. I bought some water, added it. (very little coolant was
gone from the res.; I have been checking the res. in the last several weeks and have
not seen a problem. Nor is there a spot on my garage floor, upon inspection. )

The leak was again noticable when I parked in the garage, but it again ceased. No appreciable
coolant loss. Looking underneath the car, it looks like the area just forward of the oil pan
has coolant splashed about. There are 4 hex bolt heads there. The water pump in dry
underneath.

Any guesses? Did I blow the radiator? I can't find anything on/near the rad. hoses.

 

[Ken]

It's a radiator alright, but not the one you're thinking of; it is the heater core I'll bet. You may have just developed a leak in one of the heater hoses where it connects to the core, but most likely it's time for a replacement.

It's not at all unusual for a car that's as old as yours, and age is the key factor most of the time, not mileage, unless it (the cooling system) was sadly neglected, then it would need to be replaced sooner.

 

[Top]

Sounds like a small pin hole leak in the heater core or the hoses inside. If it breaks wide open you will have a flood in the car. It leaks when the car is hot and under pressure. When you are cool and in the garage it will not leak because the stat is closed and the coolant isn't flowing. You could try some of that stop leak stuff or as my grandfather used......pepper. I would replace it

Good news is there are lots of cheap heater cores on ebay. Bad news is it is a pain in the rear end to pull everything to replace it.

Good Luck!!

 

[Yarls24]

I had that happen to me, it turned out that the factory clamp was not holding the heater hose tight enough going in to the firewall. Try a new clamp, it might work. I thought mine was a bad heater core too. If the hose is new, its possible the factory clamp can't squeeze it tight enough.

 

[69MyWay]

Been there, done it, didn't get a t-shirt!

Ugly job my friend......The Late C4 dash is a pain to gain access to this compartment. Take photos, and go slow. You can damage more than you fix if you are not careful.

I replaced mine last year.

 

[sothpaw]

heater core, please, no!

...I already had the heater core replaced in this car!! It was the second extraordinary maintenance item that I had to take care of. Back in '98, when I bought the car, the heater never worked well. That winter, the windows did start to fog up, but not like last night.

I just had the antifreeze changed last fall, it was 2.5 yrs old, I thought that was ok. I have
been keeping tabs on it.

I do have the peculiar habit of not asking this car for heat as I don't drive it much in winter,
and this winter I left my 160 stat in so I did not want to run the heat--I wanted the car
to get warm.


Pretty Please tell me it could be something else!? Clearly, it's a small leak.

 

[sumoboy]

Do you see anything leaking outside the car. You might have to pull the carpet up on the pass side to see how wet it is. You might not notice it as bad on the carpet but as it soaks it up you'll see where it's going.

 

[resto75]

If you don't use the heat and want a quick fix just take off the expansion tank and remove both heater hoses to the core. Then connect the two hoses together with a new piece of heater hose or you can just reposition the one from the tank so it will connect to the other hose further down the line. This will by pass the core but you will never have heat again.

 

[rrubel]

Sothpaw! Quick - sell yours and buy 69MyWay's! .

FWIW, also sounds to me like the heater core. If you had it replaced already, did they use new or rebuilt?
[RICHR]

 

[Eagle85C4]

In their infinate wisdom the engineers placed a vacuum operated isolation valve for the heater core. Where the send and return tubes for the heater core enter the engine compartment on the passenger side you will see the valve with the vac hose attached. If the valve is functioning it should isolate the H/C...if not like it was mentioned earlier you can remove the two short pieces of hose between the valve and the firewall and with a piece of new hose jumper the tubes closest to the valve together effectivly removing the H/C from the loop. Then you can replace at a later date seeing the summer is just around the corner and heat will not be needed.

 

[sothpaw]

iso. valve, expansion tank?

Where exactly are these located, are they easy to get to
or do I have to take apart the dash to get to them?

I would take it to someone else to do anything major, but
if it's something covered in the Haynes manual or the
early shop manual (I don't have the real one, I have the
preliminary) I might well give it a shot?

RichR,

No, Paul wouldn't put a used Heater core in there. I recall the
part being pretty cheap as it was. The labor is what is expensive.


Sumo,

I dried out the carpet without removing (removed floor mat) and
so did not see a thing.

 

[sothpaw]

exp. tank, iso valve

If I bypass, will my AC still work? My front Windshield defroster?

 

[Eagle85C4]

Plese re-read my last post. I believe I explain the position of the valve and related hose clearly. Passenger side of the engine compartment. That is under the hood. You will see two short
(4"+/- 1 inch) hoses going back into the firewall. There will be a clamp on either end of the hoses. The hoses are attached to the heater core on the firewall side. Coming away from the firewall the hoses are connected to some tubing, if you follow the tubing you will see the isolation valve with a very small piece of vacuum tubing attached to it.
Now go back to the 2 short hoses, remove the clamps. Take a knife and slit both hoses to remove them. Now take a piece of hose and jumper or loop the two pieces of tubing NOT attached to the firewall. This will effectivly remove the heater core, the two tubes coming out the firewall, from the engine cooling system and will stop the influx of coolant into the passenger compartment.

I hope this is clear enough as I do not think I can explain it with any more clarity then already presented. Good Luck....Just ask if you require any more help.

One note worthy comment: Disregard any reference to expansion tank as there is nothing like that within the confines of the engine compartment or necessary to bypass the heater core....

 

[sothpaw]

Eagle,
Thanks, that is much appreciated.

Do you now if the front windshield defroster would be even a
little effective with no heat? I ask because on occassion, you
get condensation and need to remove that with the defroster.

Also, when I cut what you said to cut, I assume I should be
ready to catch some antifreeze?

 

[Vettelt193]

the defrost will still work ok with the air conditioner on cold... all you need to do is get the inside of the glass the same temp as the outside to get rid of condensation

 

[rrubel]

Sothpaw, while Paul will not use USED parts (unless you give them to him), he will use rebuilt - most places do; for some things it's the only way you can easily get them (most major parts from the dealer are rebuilds). Pretty sure my water pump is a rebuild, for example.

If you want, bring it down here sometime and we can go over it.

[RICHR]

 

[sothpaw]

New/ rebuilt,

I guess I should have asked. With the labor cost and the shop
down time, there's no way I would want a rebuilt one in there.
That goes for just about anything vital to the operation of driving
the car.

 

[Nut]

southpaw,

Take her down to Corvette Performance on Phil. Rd in Rosedale. Ask Keith (the owner). He'll give you a straight answer and fix it right if you so choose. Tell him Bob sent you. Good guy. I have the work I can't do myself only done there.

............. Nut

 

[sothpaw]

Thanks Nut,

I might just try him in the future. I'm enticed right now by the
possiblilites of doing this myself.

Eagle,

When I do the "jumper", I suppose I need hose clamps in addition
to the hew hose to make the new connection? Also, do I have to
worry about contaminating the system by exposing it to air
(thru open hoses when I cut the h/c intake return)?

 

[Eagle85C4]

You can reuse the existing hose clamps. You should get a new piece of hose. Now if you do not use heat and want to bypass the throttle body as well now is the time to do it. At the front of the intake there is a short hose that goes up into the throttle body, on the passenger side of the throttle body the hose exits and goes to the heater core via the tubing bolted to the fenderwell next to the right front tire. After it loops through the H/C then it returns to a 3/4" nipple off the water pump, under the Air conditioner. To bypass it all, remove the hose from the intake to the throttle body, remove the hose going to the nipple on the water pump under the air conditioner. Then run a new 3/4 inch hose from the intake to the nipple on the water pump. Then you will have bypassed the throttle body and the heater core.

I just spent the last 2 days replacing the water pump in my 85 what a bear...replaced it with a high flow CAT pump form california and it made a big difference. While there I replaced every coolant hose from the pump to the H/C to the oil cooler and back as I believe in preventative maintenance and have a strong dislike for breaking down in the middle of nowhere because I was lazy and did not do the job right...that is a lesson you learn only once...