Ahhh, the sweet smell of antifreeze...HELP!

[snampro]

Info on the car: 1994, K&N air filters, Roe high-flow cats w/Borla mufflers, 56K miles, Arrow rebuild in 2000 at 30K miles, currently have a V-mania top and side windows (yes it matters for this), coolant levels in BOTH tanks are correct.

What's happening: Driving the car, if I go full throttle through at least one gear I smell antifreeze in the cabin. The smell is more intense if the temp control dial (heater core valve) is wide open than if it is closed. With the hood open the smell of antifreeze is strong at the right rear of the engine, around the cabin air intake.

What I've checked: Visual inspection all around the engine, all hoses, intake manifold everything, nothing seems to be leaking (did this with the car off and running). Did an oil change a few days ago and looked over the sides of the block from the bottom, didn't see anything coming from the heads. Just pulled off the windshield wiper visor and cabin air intake box to get a closer look at hoses and right side of the engine, nothing. No coolant leaking in the passenger foot well. No coolant leaking from the car to the floor of my garage.

What I think is happening: Small leak in the heater core, heater core needs to be replaced... I think I hadn't noticed it because, since I bought the car in September, I have rarely driven it with the top and windows on, and when I did, I was taking it easy.

What do you guys think?

 

[Randy]

The Gen I engine has a fairly common problem of coolant leaking around the thermostat housing junction with the block (both sides of the V). I had to have the gaskets replaced three times on my Gen 1, the last time opting for very thick aftermarket gaskets and a liberal application of permatex, which finally seemed to address the problem. The leak will often not be easy to find, as often the coolant leaks onto the valley on-top/between the banks of cylinders, and as the thermostat is mounted at the back of the block, its hard to check without removing the windshield cowl and perhaps the intake.

 

[snampro]

Looked over the car closely again and notice a little discoloration at the top of cylinder #10's plug socket. I don't see how it could be coolant, though. I'll post pics in a second.

Also, sniffing around the blower motor I don't smell the coolant smell as strongly as I do at the back of the right side of the engine. I still don't see anything leaking.

EDIT: here's a closeup of the number 10 cylinder plug and socket

 

[snampro]

The Gen I engine has a fairly common problem of coolant leaking around the thermostat housing junction with the block (both sides of the V)...

I looked in the valley under the intake manifold and didn't see anything there, it could be leaking down the back of the block from the thermostat, though.

Thanks for the heads-up on the thermostat, it would be really nice if that's all it is because it's not leaking much, it must just be a little bit.

where did you get the aftermarket gasket?

 

[Jeff Torrey]

If the leak has just started you may be able to re-tourque the bolts and save it. The bolts loosen over time, torque specs are very important.

 

[Jeff Torrey]

It's hard to see the leak because the fluid evaporates very quickly in the valley of the block.

 

[Greg 99ACR Red and Silver]

I have a Gen 2, but you should check the inlet to your Heater Control Valve. I had the "smell" and it turned out to be a slow leak around the factory hose fitting. The photo shows the screw-on clamp that I fixed it with. I cut off about 1/2 inch from the hose and shoved it back on.

The valve is in such a position that fumes from even a small oozing leak is drawn into the cabin and can be smelly. Worth a look!

 

[snampro]

If the leak has just started you may be able to re-tourque the bolts and save it. The bolts loosen over time, torque specs are very important.

are you talking about the thermostat housing bolts? can I get to those without removing the intake manifold?

I have been planning on upgrading my coolant system with silicone hoses, a new thermostat, new radiator, and a new fan, I guess this is just a good reason to get it done soon. Although, if tightening bolts will fix it I'll give it a try.

 

[snampro]

inspected the heater valve area, no obvious sign of a leak, I guess I can buy some screw hose clamps to see if that helps, here's a pic:

 

[Greg 99ACR Red and Silver]

If you can't see fluid or smell a leak it's probably OK

 

[snampro]

If you can't see fluid or smell a leak it's probably OK

thanks for the info, though, something to keep an eye on.

I can't smell anything there, the smell is strong from the back of the engine.

 

[Jeff Torrey]

The leak usually starts at what's called the cross over tubes. You don't have to take the intake off to tighten it back down. You will need an extention and a swivel for the tourque wrench. It's where the tubes bolt into the block.

 

[snampro]

The leak usually starts at what's called the cross over tubes. You don't have to take the intake off to tighten it back down. You will need an extention and a swivel for the tourque wrench. It's where the tubes bolt into the block.

couldn't find specific torque numbers in the manual for the crossover bolts, but it looks like the thermostat bolts are all 23ft-lbs so I used that. Son of a ***** those four cross over tube bolts (two on each side of the engine) are hard to get to, but I managed to torque all four, the lower one on the right side (where the smell is coming from) moved a significant amount, the other three didn't move much at all.

 

[snampro]

check that, I meant to say 23 Nm...

 

[Phil Lee 94 red RT]

The smell is more intense if the temp control dial (heater core valve) is wide open than if it is closed

Heater core could be bad. Mine had to be replaced back in 1998.

 

[Tom F&L GoR]

The temp control valve is only an inlet valve. The system pressure will still act on the heater core, so it could leak whether there is flow or not, since there is pressure all the time.

I had to replace the valve because the lower stem seal leaked. Because I sealed the coarse foam rubber gasket under it, the coolant puddled on the top of the footbox. I had found the foam rubber can get saturated and eventually rain water wicks through, so I used windshield sealer, a very runny version of silicone glue, to seal it. Maybe your valve stem is leaking - stick your finger in the black foam and see if it is wet and/or smells like coolant.

 

[Randy]

If the leak has just started you may be able to re-tourque the bolts and save it. The bolts loosen over time, torque specs are very important.

are you talking about the thermostat housing bolts? can I get to those without removing the intake manifold?

You can get to the thermostat housing without removing the intake - its difficult, but still easier than removing the intake. You'll have to remove the cowl in front of the windshield (less than five minutes - remove the windshield wipers - one bolt each under each cap - and the four screws). Note that the thermostat housing bolts are *inverse* torx, though - they look like a big torx screwdriver head. So, if you don't have the inverse torx socket set, be prepared for a trip to your tools supplier first. And, although its been four or five years since I worked on this, I seem to recall that you'll need a U-joint on the wrench to get to one or two of the bolts.

Concerning the heater hose - that was a known problem and I think it was a TSB bulletin for the Gen II, but not the Gen I. I never had any heater hose or heater core issues with my Gen I in 70k miles - not to say you won't, especially if its been sitting much, but everyone I know with a Gen I eventually developed the thermostat housing leak, so its probably more likely.

Gaskets: It was under warranty for the first two repairs and I'm sure the tech used the stock gaskets. The third (or was it the fourth?) time it happened, it was out of warranty, and we used the aftermarket gasket material where you cut it to shape yourself, simply because it was much thicker than the stock material.

 

[2001 GTS]

I've had a small amount of coolant leaking by the heater hose once and awhile, but tonight it happened again but the heater hose was dry and the right rear of the engine bay had a fair amount of sitting coolant around that area. Does this sound like just the heater hose or something more?

Note: GENII GTS

 

[ROCKET62]

So just to clarify - how much coolant are you loosing?

 

[2001 GTS]

Less than 1 oz...if that. Only happens when I floor it through a few gears. Its weird though, it didn't happen for a few months, now yesterday it did it twice. What do you think?

 

[snampro]

sorry guys, I started another post when I fixed the problem, I'll try to find it and link it here.

Edit: found it...HERE

 

[2001 GTS]

thanks