Heater Core question

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

tj43

Full Access Member
Joined
Jun 20, 2022
Posts
77
Reaction score
192
Location
Little Rock
First Name
TJ
Truck Year
1988
Truck Model
V1500
Engine Size
350
My 88 Burb appears to be leaking at the heater core. Are any of the replacement options better than others (I know quality on things like radiators and AC compressors can vary greatly)? If there is a quality option, can someone point me towards it? I’m willing to spend more money to have a part that will last another 36 years.
 

PrairieDrifter

Full Access Member
Joined
Dec 28, 2014
Posts
3,844
Reaction score
5,634
Location
North Dakota
First Name
Mason
Truck Year
84,79,77,76,70,48
Truck Model
Suburban k10, bonanza k10, k30, k20, c10, gmc 1/2ton
Engine Size
350, 350, 350, 350, 350, 350
I would recommend a brass/copper core. Can't remember the brand. Like factory had. The aluminum ones seem to not fit properly, that'll ruin your heating capability. I got mine from summit it was a perfect fit, going on 6 or 7 years now.
You must be registered for see images attach
You must be registered for see images attach
 

Soundmound

Supporting Member
Supporting Member
Joined
Feb 15, 2022
Posts
1,809
Reaction score
5,465
Location
North Central Washington
First Name
Dave
Truck Year
1984
Truck Model
Scottsdale
Engine Size
305
I would recommend a brass/copper core. Can't remember the brand. Like factory had. The aluminum ones seem to not fit properly, that'll ruin your heating capability. I got mine from summit it was a perfect fit, going on 6 or 7 years now.
You must be registered for see images attach
You must be registered for see images attach
Second this. Tried aluminum and fit was trash. Ordered a brass unit from Summit and perfect fit.
 

rwjtexas

Supporting Member
Supporting Member
Joined
Aug 11, 2022
Posts
81
Reaction score
109
Location
Beaumont, Texas
First Name
Rob
Truck Year
1985
Truck Model
K5
Engine Size
6.2L Diesel
Agreed ... I put the brass from Summit in mine as well last year ... since the Radiator is brass ... I wanted my heater core to be brass ... in my 85. Aluminum has a tendency to wear out faster ... of course it is half the price but the same amount of work to pull the heater box out and to save $ 40.00 ... it is not worth it not going with the brass
 

tj43

Full Access Member
Joined
Jun 20, 2022
Posts
77
Reaction score
192
Location
Little Rock
First Name
TJ
Truck Year
1988
Truck Model
V1500
Engine Size
350
Thanks fellas. Going to order the brass/copper unit from Summit. Anything else I should replace “while I am in there?” Is the evaporator in the same box as the heater core?
 

PrairieDrifter

Full Access Member
Joined
Dec 28, 2014
Posts
3,844
Reaction score
5,634
Location
North Dakota
First Name
Mason
Truck Year
84,79,77,76,70,48
Truck Model
Suburban k10, bonanza k10, k30, k20, c10, gmc 1/2ton
Engine Size
350, 350, 350, 350, 350, 350
Thanks fellas. Going to order the brass/copper unit from Summit. Anything else I should replace “while I am in there?” Is the evaporator in the same box as the heater core?
You'll need to replace the fire wall seal and foam. Just some single sided foam tape, a little silicone and some cleaning. The evaporator is on the firewall side box, you won't have to mess with that to complete the heater core job.

You could get a cheap vacuum tester and check your vac cans on the box, wouldn't be a bad idea. Make sure they actuate properly.
 

ali_c20

Full Access Member
Joined
Sep 20, 2016
Posts
1,291
Reaction score
1,841
Location
Austria
First Name
Alexander
Truck Year
1974, 1979
Truck Model
C20, K5
Engine Size
350, 350
Thanks fellas. Going to order the brass/copper unit from Summit. Anything else I should replace “while I am in there?” Is the evaporator in the same box as the heater core?
Leak test your heater core before you install it.
 

rwjtexas

Supporting Member
Supporting Member
Joined
Aug 11, 2022
Posts
81
Reaction score
109
Location
Beaumont, Texas
First Name
Rob
Truck Year
1985
Truck Model
K5
Engine Size
6.2L Diesel
While you are at it ... I would replace the Fan Motor and squirrel cage along with the 5/8" and 3/4" heater hoses ... once done .. done....

Make sure you attach the vacuum lines before nutting up the box ... it will be a lot easier to get a fat hand on the the tips if you can move the box slightly instead of having to trying to get your hand on the firewall side to get the AC / Heat lines connected. Be sure you remeber which is which ...

TAKE PICTURES ... they are priceless ....

Also watch as many You Tube videos as you can on the secret to remove and install the blend / dampner door.

One last piece of advice ... if yours is not damaged, I would still consider replacing the blend door connector with an aluminum one ... the factory plastic ones break and you are screwed.

And the tip of the day ... if you strip out the smaller holes for the #8, #10, screws, use a small 4" zip tie in the hole all the way in from the screw side, ... screw in slowly and don't over tighten, they will hold just fine .. take some end nips and clip the tie smoot with the screw. ... I know .. it does work. :)

 
Last edited:

tj43

Full Access Member
Joined
Jun 20, 2022
Posts
77
Reaction score
192
Location
Little Rock
First Name
TJ
Truck Year
1988
Truck Model
V1500
Engine Size
350
Summit core showed up and looks good. Went ahead and ordered some foam tape and constant tension hose clamps from Amazon (should be here today). Going to try to tackle the swap this weekend. Thanks again for the advice and direction. That's why I love this forum :favorites13:
 

75gmck25

Full Access Member
Joined
Oct 13, 2016
Posts
2,254
Reaction score
2,194
Location
Northern Virginia
First Name
Bruce
Truck Year
1975
Truck Model
K25 Camper Special TH350 NP203
Engine Size
5.7
There is one bolt that is very hard to reach because it’s down behind the edge of the inner fender. You can unbolt the inner fender to get space for a regular wrench, or some folks have used various universal joints to get in there.

You will need an assistant when you bolt the housing back in, because one person pushes it in against the new foam gasket, and the other person screws it down as the bolts push through. Not really hard, but both folks need some agility to fit in there.

I also 2nd the suggestion to replace the plastic fitting on the blend door, and also check the vacuum pod operation and the condition of the vacuum lines.
 

rwjtexas

Supporting Member
Supporting Member
Joined
Aug 11, 2022
Posts
81
Reaction score
109
Location
Beaumont, Texas
First Name
Rob
Truck Year
1985
Truck Model
K5
Engine Size
6.2L Diesel
Agree with @75gmck25 I discovered when I pulled my heater box ... IF you have not pulled the inner fender, you will find out that you have sooooooo much room to work with the wheel and inner fender off .. it is a pain .. yes, but you will find out why when you start working on the box.
 

Bennyt

Full Access Member
Joined
May 17, 2019
Posts
1,196
Reaction score
1,846
Location
Surprise
First Name
Ben
Truck Year
1977
Truck Model
C10
Engine Size
350
Just a reminder...

If you use any aluminum in your engine; radiator, heater core, intake, heads, block, etc., you should install a sacrificial anode. They cost $20 and can help protect your parts.
Also, always use distilled water.
You must be registered for see images attach
grading of aluminum.
 
Last edited:

tj43

Full Access Member
Joined
Jun 20, 2022
Posts
77
Reaction score
192
Location
Little Rock
First Name
TJ
Truck Year
1988
Truck Model
V1500
Engine Size
350
Box came out pretty easy. I got it split apart and the new Summit core fit nicely. Buttoned her back up with the aluminum blend door latch and pin (thanks for that pointer—the original definitely broke as soon as I touched it).

I have everything cleaned up and ready to go back in the truck. Now I just need some free time to reinstall everything.
 

Attachments

  • IMG_2901.jpeg
    IMG_2901.jpeg
    121.3 KB · Views: 48
  • IMG_2902.jpeg
    IMG_2902.jpeg
    143.3 KB · Views: 53
  • IMG_2903.jpeg
    IMG_2903.jpeg
    120.1 KB · Views: 50
Last edited:

tj43

Full Access Member
Joined
Jun 20, 2022
Posts
77
Reaction score
192
Location
Little Rock
First Name
TJ
Truck Year
1988
Truck Model
V1500
Engine Size
350
I should add (in case it helps folks in the future): the “hidden” nut near the inner fender was a breeze to get off using a long shank socket, a u-joint “wobble” adapter, and a 12 inch extension on a half inch drive ratchet wrench (1/4 might be even better for wrench swing in the tight area around the inner fender and AC box).


You can cup your hand under the socket and guide it right onto the stud—which is pretty long and makes indexing onto the nut relatively easy.
 
Last edited:

Latest posts

Forum statistics

Threads
44,115
Posts
949,550
Members
36,210
Latest member
dougjdg
Top