p38 heater core replacement - pics & tips

hey folks,

Just wanted to share some of the fun I've been into the last couple hours. After smelling coolant inside the vehicle I skimmed the wonderful internet to find advice leading to the heater core. Well sure enough it was leaking and I could actually see it leaking prior to doing what you see in the photos.

TIP: I used the base model electric Dremel rotary tool with quick attachment metal cutting discs to cut the frame. Don't forget to wear goggles! (dont get the battery powered dremel it sucks)

TIP: There are 2 bolts holding the frame solid where I circled in red - It stumped me for 20 mins why I couldn't bend the dash frame forward until I found the upside down bolt (10mm wrench I believe was the size)

TIP: cutting the plastic vent pipe I circled in yellow is almost impossible to cut without the proper tools - I ended up using a drill bit and drilling it until I basically sawed it off using only the drill bit.

I have a few questions

#1 do I have to drain the coolant before removing it?

#2 (if yes to #1)once I drain the coolant how much coolant will leak inside the vehicle once i remove the heater core?

#3 (#2 ifso) should i wedge a towel up under the heater core connection expecting the flood of coolant?

#4 the only thing I broke in the process was the plastic clamp that held on a sensor? indicated by the red arrow in the photo(what is that? should I get creative and clamp it back on by other means?)

#5 can I get replacement seals for that heater core connection? its clearly leaking from the connection

#6 should I just replace the whole thing to avoid replacing it in the future?

babytoes said:

hey folks,

Just wanted to share some of the fun I've been into the last couple hours. After smelling coolant inside the vehicle I skimmed the wonderful internet to find advice leading to the heater core. Well sure enough it was leaking and I could actually see it leaking prior to doing what you see in the photos.

TIP: There are 2 bolts holding the frame solid where I circled in red - It stumped me for 20 mins why I couldn't bend the dash frame forward until I found the upside down bolt (10mm wrench I believe was the size)

TIP: cutting the plastic vent pipe I circled in yellow is almost impossible to cut without the proper tools - I ended up using a drill bit and drilling it until I basically sawed it off using only the drill bit.

I have a few questions

#1 do I have to drain the coolant before removing it?

#2 (if yes to #1)once I drain the coolant how much coolant will leak inside the vehicle once i remove the heater core?

#3 (#2 ifso) should i wedge a towel up under the heater core connection expecting the flood of coolant?

#4 the only thing I broke in the process was the plastic clamp that held on a sensor? indicated by the red arrow in the photo(what is that? should I get creative and clamp it back on by other means?)

#5 can I get replacement seals for that heater core connection? its clearly leaking from the connection

#6 should I just replace the whole thing to avoid replacing it in the future?

Click to expand...

1). Yes, else you will get a lot of coolant in the car..!!

2). With luck, you could get a glass full at most, usually from inside the heater core.

3). Yes.!!!

4). It is the heater core temp sensor, it tells the HEVAC system when the coolant is up to tmperature and to allow the heater to fully utilise the hot air should it be required to maintain comfort levels. Not sure if a makeshift job will suffice, I am sure the sensor is not expensive so may as well replace it if you can.

5). Oh yes, replacement O rings are a very common job on the P38...not sure where in the world you are (LHD vehicle obviously - and from your hashes indicating numbers I assume the US...) but in the UK one would try Ebay ....make sure you get a new bolt to clamp it all together, the original is pretty crap.

6). If the heater cores are fine with no defects, just replace the O rings and bolt. and job done...if funds allow, you may aswell replace the heater core if you have any doubts on it's condition.

Good luck with it.....it is not a job I am looking forward to doing....being a RHD car, I have the Steering column and pedals to contend with too!!!

Yea I'm in the US - Where better to get advice on this vehicle than where it came from?

Thanks for the quick response Saint.

Dude you have no idea how easy you have got it with the car being LHD. I changed my matrix last year and as Saint says it is a whole different level of ****ed up on a RHD model.

When I done my heatet o rings I got no fluid in the car I drained the rad and then disconnect the mattix hoses in the engine bay and blew down.them.very hard just remeber not to suck or get it in ur face hope it helps u

ok guys a little update:

I replaced the seals on my old heater core first off. Refilled the fluid and it leaked. GGrrrr!

So I bought a new heater core with rings... it came in I switched it all out tightened it down filled it up and bam no leak. A week later I'm driving along and hear a gurgling noise lean over and sure enough fluid is leaking down into my floorboard again. SON OF A BITCH!

So as of right now I have the flexible hose just before the firewall bent backwards & connected bypassing/blocking off fluid to the heater core.

I am very ****ed at the way this connection was designed, I have a feeling it would have been easier more reliable to replace/retighten if I had taken off the whole dash...but who the hell wants to that?

So my plans in the future are to remove the the heater core - saw off the connecting metal pipes that will include the o-ring connection so that I can attach the pipe to the heater core in plain view before putting it back in. Use standard hosing and clamps to fuse the pipes back together. Thus leaving no room for error where the o rings join the heater core.

hope this helps some unlucky soul down the road

PS: ill try and be grateful that I have a left hand drive

babytoes said:

ok guys a little update:

I replaced the seals on my old heater core first off. Refilled the fluid and it leaked. GGrrrr!

So I bought a new heater core with rings... it came in I switched it all out tightened it down filled it up and bam no leak. A week later I'm driving along and hear a gurgling noise lean over and sure enough fluid is leaking down into my floorboard again. SON OF A BITCH!

So as of right now I have the flexible hose just before the firewall bent backwards & connected bypassing/blocking off fluid to the heater core.

I am very ****ed at the way this connection was designed, I have a feeling it would have been easier more reliable to replace/retighten if I had taken off the whole dash...but who the hell wants to that?

So my plans in the future are to remove the the heater core - saw off the connecting metal pipes that will include the o-ring connection so that I can attach the pipe to the heater core in plain view before putting it back in. Use standard hosing and clamps to fuse the pipes back together. Thus leaving no room for error where the o rings join the heater core.

hope this helps some unlucky soul down the road

PS: ill try and be grateful that I have a left hand drive

Click to expand...

Bummer. But your solution sounds good. I hope it works out. And remember, left hand drive is the drive of the free and the steering of the brave.