99 bonneville antifreeze smell
 

Hey guys just replace uim on 99 bonne couple weeks ago thought that was my smell. I have smell inside car only with heater on. Could this be the heater core,never had heater core trouble with my 94 with 240000 on it. If so how much of a pain is it to change? Thanks guys

That's a good indication of a bad heater core. Not sure of the difficulty on removing it, I could try and look it up in my 95 fsm.

If I'm not mistaken, that's taking the dash off to get to it.

This might work....

https://www.gmforum.com/showthread.p...ht=heater+core

Yup to that link. shouldn't need to take the dash off. I've had the occasion to look at the heater core a few times when doing an air mix actuator swap. Looked like ti would come out w/o dash removal.

One thing to note here. I'd automatically have fresh heater hoses and a spring clamp tool on hand. The hoses connect to the core behind teh strut tower in your year. It's a tight space. I found that the spring clamp tool worked wonders and then the hoses didn't want to cooperate. With such limited accessiblity, I sliced the hose lengthwise and peeled them off the core.

New hoses and spring clamp tool were a key to success.