Engine/Transmission (1998.5 - 2002) smell coolant

[RCrosby]

Yes when heater is turned on, the smell of coolant is coming from vents. Is this a hard job to replace the heater core. I tryed bars stop leak, it did not help. should I pressure test it are just get ready to change core. I do not see any coolant on floor or there is a drain.

 

[DavidC]

Yes there is a drain on passenger side firewall. Changing the core is not necessarily hard but involves quite a bit of work getting the dash in a position where you can work on it. That smell can also be caused by a cracked 53 block, hope you do not have that. There are a few posts on here if you do a search on replacing the core. Do your body stretches as some awkward positions are involved.

Dave

 

[RCrosby]

I remember back a few years ago i check to see if i had the 53 block, don't remember how to check for that. the only time i smell coolant is when the heater is on. how the 53 block crack could cause that also.

 

[DavidC]

The 53 is a raised large number on Drivers side around the Vp 44 if I remember right. How the smell happens is drawn thru the outside intake and pumped out the vents. Max air is the only time outside air is not used and recirc's only inside air. The crack in the 53 is usually behind the heat exchanger on the passenger side. There is also the case of the heater core with what starts as a minor leak and could show up in colder weather fogging the windshield with the defroster on. Just listing the options of your dilemma.

Dave

 

[SAndreasen]

The 53 can also be on the passenger side of the block that is where mine is if you do a google search there is a page that has all kinds of info on the 53 block the 53 can be in several places not just the drivers side of the block . The good news is if it only does it when the heater is on it is most likely the heater core

 

[KrisKringle]

Heater core advice

Hello...just a bit of advice if you end up having to swap out the heater core: I had a bad experience with the replacement heater core, (the one with articulated lines). After only two years the Chinese POS (from Rock Auto) developed a leak at the unions. I swapped it out with the original copper version. It was not any harder to install than the other version.

Oh, and Also, you should plan to replace the foam "weather-stripping" on the doors while you have the thing out. Make sure you have the correct size, and clean and prime the surfaces prior to installing the new strips...I found out the hard way...

 

[DClark]

The 53 is a raised large number on Drivers side around the Vp 44 if I remember right. How the smell happens is drawn thru the outside intake and pumped out the vents. Max air is the only time outside air is not used and recirc's only inside air. The crack in the 53 is usually behind the heat exchanger on the passenger side. There is also the case of the heater core with what starts as a minor leak and could show up in colder weather fogging the windshield with the defroster on. Just listing the options of your dilemma.

Dave

I can tell you that 53 blocks can fail internally. Ask me how I know? Mine dumped a mixture if oil and coolant on the ground and there was no external leak. Took the engine out and tore it down and never found where it failed internally. Just replaced with a recycled non-53 block (hard to find). Hope yours is not a 5 block problem. Good luck with the coolant smell.
DClark

 

[rickybobby]

KrisK where do you get the foam for the heater core box door. Regular self adhered weather stripping for windows and doors? I'm going to be doing mine soon and A/C evaporator. No problems with them yet. I bought a new dash from LMC cause the original is crack to heck. I figured while I'm there might as well swap them out as recommended by Genos.

 

[BMelhuish]

Here is a TDR article on how to change out the heater core without removing the HVAC box. Honestly though, if you're going to all that work to replace the heater core, you may as well go all in. You still have to pull the dash back. If it hasn't been done already, you may want to consider replacing the AC evaporator core and repair anything else that requires removal. It's not a difficult or even a time consuming job.View attachment PagesfromTDR_46_Issuu.pdf

 

[hcole]

Yes when heater is turned on, the smell of coolant is coming from vents. Is this a hard job to replace the heater core. I tryed bars stop leak, it did not help. should I pressure test it are just get ready to change core. I do not see any coolant on floor or there is a drain.

Well, mine started leaking just enough so you could smell it occasionally about 18 months ago and I changed the thermostat to a 180* and changed the radiator cap to a 7 LB. It was losing about a cup of water a week before and now none. No more smell and engine runs cooler like my 91.5 did. I think now that the 7 LB. cap was the difference because the system can't pressurize more than 7 Lb.s and goes into the overflow tank when hot and is drawn back into radiator when it cools. I've checked it hot and never seen the overflow tank with any noticeable level change. Evidently the heater core had a high pressure leak and this change stopped it.

 

[SAndreasen]

Yes when heater is turned on, the smell of coolant is coming from vents. Is this a hard job to replace the heater core. I tryed bars stop leak, it did not help. should I pressure test it are just get ready to change core. I do not see any coolant on floor or there is a drain.

So what did you find out

 

[SAndreasen]

I can tell you that 53 blocks can fail internally. Ask me how I know? Mine dumped a mixture if oil and coolant on the ground and there was no external leak. Took the engine out and tore it down and never found where it failed internally. Just replaced with a recycled non-53 block (hard to find). Hope yours is not a 5 block problem. Good luck with the coolant smell.
DClark

Please tell me how if it was leaking internally how did the coolant oil mix become visible externally?

 

[DClark]

Please tell me how if it was leaking internally how did the coolant oil mix become visible externally?

Sorry for the late response. I do not know how it leaked out. It just came from the front of the engine somewhere and was on the ground. Mechanic could not find the failure point and I didn't want to pay him to look too much. It was not an external crack that we could see and not the head. That's all I know.
DClark