Heater control valve help....

RimoniManu

Original poster
Member
May 13, 2012
9
So for some reason my engine decided to overheat a bit and in the process ruined my heater control valve. This will be my third time replacing the Damn thing and im bloody sick of it lol. Does anyone know if there is a way to bypass the valve and just deal with not having heat? Also i read that the swb models don't have aheater control valve.....so Why do ext models have them but swb don't? plz give details if possible.
 

The_Roadie

Lifetime VIP Donor
Member
Nov 19, 2011
9,957
Portland, OR
I'm on a trip away from my manuals, but the EXT just has a longer loop and a second heater core for the rear. Not sure why they would add a valve to the system, but you certainly should be able to disassemble one of the bad ones and figure out how to force it to stay open.

How do you know it's bad? Low heat in the rear or no heat? Do you have the electric booster pump upgrade installed by the TSB that was issued for customers who complained about low hear in the rear?

MUCH more of a challenge, and far more important to your pocketbook than a cheap hot water valve that you could replace with a straight pipe, would be to identify why you have intermittent engine overheating episodes. :eek: I haven't heard of overheated coolant killing heater system valves, but we've all read about warped heads, and other BAD THINGS that come from lack of good cooling.

What can you share about the frequency of your incidents, and how you're troubleshooting that problem?
 

RimoniManu

Original poster
Member
May 13, 2012
9
I didn't have the low heat problem. When my engine warms up coolant would literally be gushing out of the heater control valve. This Morning I dove it around and no problems. Later I test drove it again with more strain on the engine and lost my coolant from the valve again. I was limping home getting water every chance I could.While I was stuck on the hwy I removed the valve and connected the tubes to bypass the rear heater. Tomorrow I'll get more in depth and see What's wrong. I say the less stuff there is to break the better...so I think I'll run without my rear heater.I'll take a look tomorrow but can anyone tell me on the swb how the coolant is connected to the hvac? Again I'll look tomorrow, where are the coolant lines for the rear hvac?
 

FamilyDan

Member
May 19, 2012
4
This morning my Traillazer overheated. The guy at the shop said it was the heater control valve that had gone bad and caused the truck to overheat. It sounds like a fairly straightforward swap, but what did you find about bypassing it altogether?

TIA
 

RimoniManu

Original poster
Member
May 13, 2012
9
Sorry I didn't reply earlier. So I took apart my heater control valve and there are two rubber seals..... one on top to keep the coolant in and another seal that opens when a vacuum is applied. The valve opens to allow coolant to go to the rear hvac. I never use my rear heater. My TB is always full of tools and parts anyways and I got tired of this plastic piece of $#%@ valve. What you'll need to do is two things to run without this valve. Doing this though will disable the rear heater. I'll take a pic and post details later...... on the valve there are three hoses; two are the same size and one is smaller. You will need to plug the smaller hose......this is the feed line for the rear heater. For the other two hoses you can actually get rid of one. Remove the hose that goes from the valve to the heater. From this hose remove the connector for the heater. Now look on your engine block....the hose from your block to the valve is the feed line for both front and rear heaters. You can connect the hose from your block to the front heater directly. If you remove the hose from the engine you can cut it so it won't kink when you connect it to the heater. I think mine is about 4 or 5inches and then insert the fitting you removed from the other hose. Sorry, I suck at explaining things. Basically connect the coolant hose from engine to the heater, plug the left over hose and you're good.
 

RimoniManu

Original poster
Member
May 13, 2012
9
Also, you can always replace the valve but just letting you know the valve sucks. I've replaced it three times til this last time and got rid of it. Just think..... driving down the hwy and this valve goes...... all your coolant is gone and you're stuck.....just my 2 pennies
 

FamilyDan

Member
May 19, 2012
4
Not that I'll need it any time soon, but I've gotta have the rear heat. I'll replace the valve and see how long it lasts. I just got the rear hvac working last Saturday. The kids need the ac in the summertime. It clicks and takes a long time to get started every time I start the truck though. Next fix, after the valve. Thanks for the response.
:thumbsup:
 

RimoniManu

Original poster
Member
May 13, 2012
9
You May want to look into what the Roadie mentioned about the tsb for that issue. Just a thought
 

FamilyDan

Member
May 19, 2012
4
I went to the parts store and picked up a new HCV today. The old one was definitely bad and leaking, but it's still overheating. I had to go back to the parts store mid-job, so it's possible that I may have accidentally swapped the two hoses (same size ones). Would this cause an overheating problem, or would it just cause heater trouble? Also, Roadie, it doesn't have the booster.

Whatever the case, I'm gonna have to take it all apart again tomorrow, I'm afraid.

:undecided:

EDIT: I think there was an air bubble in the system. Eventually, it took all of the coolant from the reservoir. After that, normal running temp! Well, after I topped the coolant off again.

Thanks for all the info on the forum. I had been on the OB, until a member told me about this board.
 

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