Heater Core Replacement Tips???-4.2 V6 Many Other Troubles
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Junior Member
Joined: Mar 2001
Posts: 1
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From: Beaumont ,Tx
Heater Core Replacement Tips???-4.2 V6 Many Other Troubles
Anyone done a heater core replacement? My Haynes book says to depressure AC system, but my bro-in-law sells AllData and his program doesn't mention that step. How bad a job is it? I do all my own maint. but with all the trouble I've had lately I'm ready to count my losses and trade for a Toyota. I have a 106 mi. round trip commute four days a week, easy straight run, all interstate. Bought truck new in 97 and performed every maint. item in the book regularly. Gas mi. always sucked even with the hwy rear end and man.
tranny. Took in for all recalls including front cover gasket. Noticed cloudy oil on my filler cap at last oil change (115,000) but nothing accumulating in pan. Did compression test and is as good as new. No obvious direction to go in to find the leak without going on a witch hunt so I put Barrs stopleak in as a last ditch effort. Slowed it off and on for awhile (checking everyday for a 8 weeks now) and stopped completely for the last 3 weeks. Disappointed since I had a Ranger that I got over 250,000 miles on the same commute and never did anything but clutches and brakes.
tranny. Took in for all recalls including front cover gasket. Noticed cloudy oil on my filler cap at last oil change (115,000) but nothing accumulating in pan. Did compression test and is as good as new. No obvious direction to go in to find the leak without going on a witch hunt so I put Barrs stopleak in as a last ditch effort. Slowed it off and on for awhile (checking everyday for a 8 weeks now) and stopped completely for the last 3 weeks. Disappointed since I had a Ranger that I got over 250,000 miles on the same commute and never did anything but clutches and brakes.
Member
Joined: Feb 2001
Posts: 74
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From: Morganville, NJ
Heater core? Yuck. Since it's basically like doing an Exploder (95+), you have to remove the entire dash.
You can't just get away with pulling just the passenger side out, you must remove the whole thing.
Take out the steering column first, then unplug every harness that attaches to the dash, drain the coolant, undo the hoses. Take out the pass side airbag and hide it away. Remove the dash, remove the heater box, some (if not all) are double nutted in, then you can remove the core from it's box. You may have to discharge the a/c as the evaporator is inside the truck. Exploders are not.
Coolant in oil, if you have no indications of an obvious leak (like the front cover) or steam out the tailpipe (head gaskets), the intake gaskets are leaking. The convoluted intake that the 4.2 uses places 4 water ports at the bottom of the intake/head surface where the bolts don't really torque them down good. And the bolts back off over time.
Since the gaskets are plastic with rubber beads, the beads give up and leak.
It's a major pita to do the intake in the truck, but doable. There is very little torque on the intake bolts as they are only 6mm fine thread bolts. something like 6 ft-lbs or thereabouts.
Once you have it off, you'll see that the head/intake surface has (if I remember correctly) 9 large holes on each side with very little solid surface area.
Hope this helps.
You can't just get away with pulling just the passenger side out, you must remove the whole thing.
Take out the steering column first, then unplug every harness that attaches to the dash, drain the coolant, undo the hoses. Take out the pass side airbag and hide it away. Remove the dash, remove the heater box, some (if not all) are double nutted in, then you can remove the core from it's box. You may have to discharge the a/c as the evaporator is inside the truck. Exploders are not.
Coolant in oil, if you have no indications of an obvious leak (like the front cover) or steam out the tailpipe (head gaskets), the intake gaskets are leaking. The convoluted intake that the 4.2 uses places 4 water ports at the bottom of the intake/head surface where the bolts don't really torque them down good. And the bolts back off over time.
Since the gaskets are plastic with rubber beads, the beads give up and leak.
It's a major pita to do the intake in the truck, but doable. There is very little torque on the intake bolts as they are only 6mm fine thread bolts. something like 6 ft-lbs or thereabouts.
Once you have it off, you'll see that the head/intake surface has (if I remember correctly) 9 large holes on each side with very little solid surface area.
Hope this helps.
Junior Member
Joined: Jan 2001
Posts: 4
Likes: 0
From: Grove City, Ohio, USA
I also have noticed a white residue on my filler cap. I'm on my second engine (4.2l) and I noticed the residue on both. The first engine blew possibly as a result of the timing cover gasket. When I noticed the residue on my new engine I posted it here and got 1 response that basically said that it may be normal to see a bit during the cold winter months. I am not seeing any loss of coolant. I took it to the dealer because I have an extended warranty on the new engine and they found that my pcv valve was clogged therefore holding moisture in. They replaced it and within a few weeks I stopped seeing the residue. Still watching closely though. Good luck.