biggins

I get a strong coolant smell when I turn my heat on. It is temporary, only lasting about 30 seconds, then the smell goes away. I don't seem to be losing any coolant though. Obviously something with my heater core but will it require replacing it because that looks like a pain in the ***. 1999 Cherokee Sport 4.0 w/194,xxx miles.

at05gt

I have the same issue with mine and its a 91', its more pungent if I turn the windshield defroster on.

dans98xj

Try flushing it out first. It could be clogged and overheating the heater core. But if you getting that smell when it is cold then you might have a small leak, maybe not enough to cover the floor pan but enough to dry off and smell after the moving air hits it from the fan.

Firestorm500

Discharge the A/C properly. Drain the coolant. Pull the dash. Replace the heater core and A/C evaporator. Reassemble and recharge.

I passed up buying a 2000 XJ because of this about 5 years ago. I was also afraid it had a cracked head, as original non-TUPY heads do on those.

I was afraid it had gotten hot too many times and blew the heater core from over pressure.

BlueRidgeMark

If you can smell it, it's leaking.

That's how that works.

You can throw in some stop leak and buy some time, and many on this board will tell you NEVER do that!! Horrors! Doom! Defeat! Despair! You'll ruin your car! Destroy your cooling system! Cause small children to die for hundreds of miles around you!

Hogwash.

Use Alumaseal and it can stay in there for a long time. It might buy you as much as a year (but probably much less). Yes, eventually you'll have to repair it, and yes, you'll need to flush that stuff out. It's fine. It can buy you some time if you can't do the correct repair now.

Best solution is to replace the heater core now, before it leaves you stranded on the side of the highway somewhere.

The worst solution is to pretend it doesn't need to be done.

Dibbons

I smelled coolant today inside and added "Alumaseal". Never use the heater here in the desert, but I turned on the heat in order to circulate the stop leak. Come to find out, even when engine was up to operating temperature, the heater still blows out very cool air. I thought I could find a valve under the hood that opens and closes the heater hoses (like most older Mopars have with A/C) but nothing doing. The heater hoses simply go in and out of the firewall without any control valve that I can see. What's up with that I wonder?

TrailerTrash

cruiser54

Blend doors in the HVAC system adjust the heat and there is no heater valve for coolant.

If you NEVER use the heater, bypass it in the engine bay if the core is leaking.

And FWIW, I don't consider the XJ a MOPAR. It was designed and built by AMC originally. Existed on its own for 4 years before Chrysler bought AMC, and another 4 years on top of that before Chrysler influence crept into the equation.

Another thing, the XJs had heater valves up until 1997. The valves were a bad idea. High failure rate.

onestrongwriter

do you smoke cigarettes? there's coolant in tobacco.. different brands seem to have different amounts and I roll my own .. I smell it often