My 1999 XJ needs a new heater core, which was previously diagnosed by an actual shop plus being pretty apparent by the increasing amount of white smoke (burning coolant?) coming in from the AC vents and heat not working. Was quoted ~$1500 for parts/labor.
I opted to delay the repair, as I only need this car to last me a few more months (until August) and haven't noticed the temperature gauge sky rocket to hot, but now it actually dies whenever I come to a complete stop.
Because used cars are so expensive right now, I'm considering paying the $1500 to get by, however, now I'm scared there could be additional problems. Could the car dying while at idle be a consequence of the old heater core (a safety feature to prevent engine overheating?) and also be resolved by replacing heater core or is this likely something else entirely that could be another $1000+ to fix?
There was actually a new engine installed a couple years ago and only has 13,000 miles on it.

Obviously no way to know for sure, but just looking for some thoughts/advice before spending any money or asking a shop to diagnose more and take advantage of my lack of knowledge.

Any help much appreciated!

 

The heater core is separate from any engine controls or sensors. In fact you can disconnect it and plug the hoses if you want to get rid of the smell. Likely your idling problem is caused by a dirty idle air controller. It is located on the throttle body and is easy to pull and clean. This fixes it the vast majority of times

 

Do you actually smell coolant in the car, see coolant on the passenger side floor, or have it fogging up the windshield with slimy coolant? Smoke through the vents is not a bad heater core, nor will a heater core leak cause engine stalling unless you get so low on coolant that you're badly overheating. A plugged up heater core (not leaking) can cause poor heat, but if it's not actually leaking, a common cause for no heat is the blend door cable or the attachment under the dash being broken. See https://www.cherokeeforum.com/f2/eas...ailure-225063/

As mentioned, stalling when stopping is most often the IAC which can be resolved by cleaning the throttle body and the IAC. It can also be cause by a worn out throttle position sensor, which typically will also cause odd automatic transmission shifting as well.

Example videos below. Tools-wise, you'll need a screwdriver, set of torx wrenchs, some carb cleaner, and an old toothbrush. I prefer to take the whole throttle body off to clean it, but you can just remove the IAC and clean the tip and the inside of the throttle body without removing it. Do not get carb cleaner into the throttle position sensor.

 

lawsoncl, yes I smell the coolant and see it coming out all front AC vents as well as the passenger floor and top dash (fogs up windshield).

 

Yup, that's a leaking heater core. As a stop gap measure, you can disconnect and plug the hoses to it for now.

 

I'm more concerned with the stalling at idle. I haven't had a chance to check IAC valve yet, but could this be due to a failed head gasket or something more serious/costly?
Hoping to keep total repairs under $2000.
Thanks!

 

I doubt you're looking at a bad head gasket or anything that serious. Having a shop replace the heater core is expensive simply because of the time involved to rip out most of the dash to get to it. What are your mechanical skills like? There are plenty of youtube videos and writeups on replacing the heater core yourself. For now, I'd just pull the hoses off the heater core at the firewall and plug them or connect them together.

For the stalling, I'd start by looking at the IAC valve. That's a pretty common problem.

 

If you are not going to repair the heater, at least block off the core, hook the inlet and outlet hoses together, antifreeze is poison, you should NOT be breathing those fumes.

 

If you are not going to repair the heater, at least block off the core, hook the inlet and outlet hoses together, antifreeze is poison, you should NOT be breathing those fumes.