Heater Core Problem?

[Splandman]

For a while now when my thermostat opens as the truck starts to get warm I get a a fairly strong odor of coolant inside the cab. There have been a few times when it was really strong and it almost seemed as if a mist came out of the vents if I had the blower motor on. I would have to have the windows down and the back glass open.

This started a few months ago and then mostly went away. Sometimes I would have a faint smell and then it would go away. Usually after the truck has been running for a bit and is good and warm it goes away completely and I can run around with the A/C on and not smell any coolant.

This morning and yesterday morning it was pretty bad. When I turned on defrost it really put a film on windshield and the odor was very strong.

I have no dampness or wet area in my passenger floor area. I also have not noticed any drop in coolant during this whole time period.

 

[MadOgre]

Your heater core is leaking and needs to be replaced. Get a rebuilt core from any parts store and then we will walk you through the process of changing it.

 

[firebane]

Hopefully you don't have AC and doing a heater core is really simple!

 

[Splandman]

Hopefully you don't have AC and doing a heater core is really simple!

I do have AC, would be tough living here in Oklahoma without it. We have had a mild summer for us though.

 

[yevgenievich]

I do have AC, would be tough living here in Oklahoma without it. We have had a mild summer for us though.

You can use the reference sticky thread on the heater core removal pictures. There are a pain to get to bolts inside the engine bay on the bottom of the hvac box. Some use contraptions out of extensions to get them, while others just remove the inner fender well.(A friend of mine did the extensions and took him longer by 20 minutes vs when I went with inner fender removal). The hole assembly inside has to come out and needs to be taken completely apart to get to the heater core.

 

[chengny]

I don't want to get your hopes up but you might want to check one thing before you tear your HVAC apart.

You say this:


This morning and yesterday morning it was pretty bad. When I turned on defrost it really put a film on windshield and the odor was very strong.

I have no dampness or wet area in my passenger floor area. I also have not noticed any drop in coolant during this whole time period.


The statements in bold are generally the litmus test for a heater core failure and you have not noticed either. Is it possible that the mist is not coolant at all but condensation from the evaporator coil? If that liquid cannot drain out of the evap housing it will do two things;

1. Smell real bad (but not like coolant)

2. Get whipped up and issue from the vents when the fan is at the higher speeds - if allowed to accumulate.


There is a drain hole on the bottom of the evap casing. It will be right up against the firewall. If is plugged up the liquid can't drain normally and will enter the cab along with the incoming air. Here are a couple of images showing it's location:

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There are a number of ways to clean it out - if you find it plugged - I will leave that up to you.

 

[Splandman]

Thanks, I will give that a shot.

 

[DrPrepper]

where might the pictures be that are refered to in #5?

 

[Honky Kong jr]

where might the pictures be that are refered to in #5?

http://www.gmsquarebody.com/threads/inner-cab-heater-ac-housing-reference-pics.4809/

 

[DrPrepper]

Thanks HK....I'll probably wear this link out in the next couple of days...

 

[Honky Kong jr]

Thanks HK....I'll probably wear this link out in the next couple of days...

No problem

 

[MikeB]

I don't know about factory AC trucks, but for non-AC trucks there a TON of heater cores out there that allow air to pass around both sides. This means your heater will barely blow warm on very cold days.

The good on the left, the bad on the right.

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:

 

[DrPrepper]

Thanks for the pointers...went with removing the inner fender well route,pictures really do tell a 1000 words...I'll be warm this winter, moving on to the A/C next...been looking for the little P shaped plastic piece that attaches to the Blend door...any thoughts on where it can be found

Thanks again

 

[Honky Kong jr]

Thanks for the pointers...went with removing the inner fender well route,pictures really do tell a 1000 words...I'll be warm this winter, moving on to the A/C next...been looking for the little P shaped plastic piece that attaches to the Blend door...any thoughts on where it can be found

Thanks again

Off another truck BA DUM TSS......

 

[foamypirate]

Thanks for the pointers...went with removing the inner fender well route,pictures really do tell a 1000 words...I'll be warm this winter, moving on to the A/C next...been looking for the little P shaped plastic piece that attaches to the Blend door...any thoughts on where it can be found

Thanks again

This guy?

https://www.classicparts.com/1971-87-Diverter-Valve-Link-Connector-W-A_C/productinfo/68-248/

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