Heater Core replacement

[Goodie]

Ok fellas it looks like I'm going to drive my Siverado when it gets cold, so I'm going to replace the heater core...

I have a few questions... I've replaced one in my mini truck

Will I have to remove the Dash?
Will I need to remove the air conditiner box in the engine compartment
Do I need to remove the fender?

let me know guys...

thanks

[Eyegore]

No
yes
no

[Goodie]

how many hours???

[Eyegore]

Depends on what your going to do with the freon, are you going to recharge, then you'll need to evacuate the system. But the overall replacement of the heater core, perhaps 2-3 hours depending on your skill level, mine being zero.

[Goodie]

Ok eyegore my unit air conditioner unit is disconnected...so just remove that and I should be able to get to the core??? it took me like 6hrs to do the one in my isuzu... I had to remove the dash take apart the heater box just a cluster F@#k

[C&C Chevy]

Don't forget to disconnect your heater hoses, and put an old towel down before you remove it.

http://www.coloradok5.com/heatercore.shtml

[piecesparts]

In most cases the replacement of the heater core on a truck like yours---don't know your exact year, but in an 81 to 87---the heater housing inside the truck and the glovebox need to come out. The outside A/C housing does NOT need to be moved what so ever. You will need to go to the outside and take some nuts off of the bolts that stick through the firewall and you will have to take some screws out of the inside of the cab (all of which hold the housing in place). Once done, disconnect the heater hoses in the engine compartment, disconnect the heater controls and the vacuum hose (Mark everything). Then with the glovebox gone, roll out the heater housing and that will let you get to the heater core holding straps. Take the core out and put in a new one. Now re-install in a reverse fashion.

[Eyegore]

Originally Posted by piecesparts

In most cases the replacement of the heater core on a truck like yours---don't know your exact year, but in an 81 to 87---the heater housing inside the truck and the glovebox need to come out. The outside A/C housing does NOT need to be moved what so ever. You will need to go to the outside and take some nuts off of the bolts that stick through the firewall and you will have to take some screws out of the inside of the cab (all of which hold the housing in place). Once done, disconnect the heater hoses in the engine compartment, disconnect the heater controls and the vacuum hose (Mark everything). Then with the glovebox gone, roll out the heater housing and that will let you get to the heater core holding straps. Take the core out and put in a new one. Now re-install in a reverse fashion.

Really,then i must have done it wrong on my 86 and 78. Did them both through the engine compartment, loosened the nuts that came through the firewall and pulled the box off, split the a/c box removed the evaporator then the heater coil, don't ever recall doing anything under the dash except putting a wrench on to back the nuts off the other side.

[piecesparts]

Originally Posted by Eyegore

Really,then i must have done it wrong on my 86 and 78. Did them both through the engine compartment, loosened the nuts that came through the firewall and pulled the box off, split the a/c box removed the evaporator then the heater coil, don't ever recall doing anything under the dash except putting a wrench on to back the nuts off the other side.

Having had to work at a poor backwater county road maintenance shop (not to mention the fact that my son's truck and mine both have had to have new cores), I got the chance to learn this fact the hard way. The whole core housing can be laid on the work bench and the core removed at ease. The last one that I did, took me a whole sum total of 2 hours to go from system filled with antifreeze back to system filled with antifreeze and working.

[Goodie]

Originally Posted by piecesparts

Having had to work at a poor backwater county road maintenance shop (not to mention the fact that my son's truck and mine both have had to have new cores), I got the chance to learn this fact the hard way. The whole core housing can be laid on the work bench and the core removed at ease. The last one that I did, took me a whole sum total of 2 hours to go from system filled with antifreeze back to system filled with antifreeze and working.

I've read something like that shortly after I noticed my heat core went bad... I wasn't planning on driving it in the cold so I just by passed the core now I will be... I'm thinking about 3 hrs for me then...

[Goodie]

Oh yeah its a 86

[jdmaffeo]

I just did my 84 2 weeks ago and it took right at 2 hours. It was all done like piecesparts said. There were I think 3 or 4 bolts by the a/c box in the engin compartment and the rest was all under the dash. Take your time and you will be supprised how easy it is!

[75shortysocal]

Originally Posted by Goodie

how many hours???

6 hours...





lol... j/k..

i pulled mine out, re-saudered the broken tube, and put it back in, took about an hour.

[piecesparts]

Originally Posted by 75shortysocal

6 hours...





lol... j/k..

i pulled mine out, re-saudered the broken tube, and put it back in, took about an hour.

The 6 hour thing is the redneck way---remove a bolt, Drink beer, remove a heater hose, Drink more beer, remove the housing, drink a lot of beer, remove the core, Forgot where the beer is--went to buy more--couldn't find the store---GAVE UP....

[bigblock79]

lol 2 hour max

[Slonaker]

Originally Posted by bigblock79

lol 2 hour max

I would plan for 6 hours if i was doing it. That's a doofus factor of 3...

Slonaker

[Ivan D.]

Here's a tip - after installing the new core, when you hook up the supply hose from the engine's intake slip some kind of flow restrictor in it just before the core - it will reduce the pressure so when you revv the engine up you won't be trying to balloon the core. Did that to my car, no core blown yet, and I do go WOT every so often and them cores are know to blow easily. Did it to the truck too after blowing core while engine break-in, never had any problems ever. For a restrictor I used like three 7/16 washers stacked on top of each other, but you can use some kind of brass bushing or something else suitable that you find rolling around in yer garage.

[Goodie]

Right on... I will do it sometime this weekend.. I will probably will change all the hoses and thermostat too...

[Ivan D.]

Yes, that's always a good idea. Actually I have to change thermostat too, I run 160F now cause I got a small radiator and no shroud, but now that it's getting colder I think I'm gonna go up to 193F and throw a shroud in there.

[piecesparts]

Originally Posted by Ivan D.

Here's a tip - after installing the new core, when you hook up the supply hose from the engine's intake slip some kind of flow restrictor in it just before the core - it will reduce the pressure so when you revv the engine up you won't be trying to balloon the core. Did that to my car, no core blown yet, and I do go WOT every so often and them cores are know to blow easily. Did it to the truck too after blowing core while engine break-in, never had any problems ever. For a restrictor I used like three 7/16 washers stacked on top of each other, but you can use some kind of brass bushing or something else suitable that you find rolling around in yer garage.

Interesting approach, I have never had that issue, to speak of. The restrictor is not a bad idea UNLESS you have a cold winter in your area.

[Ivan D.]

Just ask some of yer local Mustang guys, or anyone else who got a 302 that don't spend its live under 2000 rpms - maybe it's the pumps Ford put in those things, but they are known to blow heater cores during high revv, to the point where Ford actually put a restrictor in there. And oddly enough installing a restrictor doesn't reduce heater core output, but just the opposite - I know it don't really make a whole lot of sense, but that's what I observed in both the car and the truck. Now, blowing the core in my truck may be contributed to it being old, and our truck cores may be generally much tougher than the Ford ones, but it never hurts giving the restrictor a shot.

[piecesparts]

The idea of a restrictor in a line with hot water in it is a good idea for slowing down the flow to get more heat transfer for each drop of water. The average exchange for a heat exchanger without a restriction that is around 16 degrees across the pipe wall. The restrictor on the inlet side is good for removing surges in the system, and slowing the water down will give more exchange, but it will have limitations.

Ford is not stupid---they just don't how to spell GM.

[Ivan D.]

Figured it's something like that, slow water means more time for the water to spend in the core, and more time in the core means more time to dissipate heat, right?

[Goodie]

well bros thanks alot it was a bit more difficult...probably because of the make...and year... I had to take the damn heater box out and I had to take the screws out of the air conditioner in the front some of the screws was a biotch but i got them... I dropped the inner fender well and that made it easier... I was hoping it was simple like some of you guys said... I put new heater hoses on and I put a new starter on too...damn thing was going out so I did that too... heat is working fine... didn't tighten one of my hose like a dumb ass but its all good now... this site is awesome thanks!!!

[piecesparts]

Holy Cow---after all that and you still like us?