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Suburban Rear Heat Not Working

Well, no luck. Pulled both T's out. Neither had any type of restrictor in it. Straight through the long way, also straight thru from the "T" end. Note, that these have not been changed out in the 8 years that I've owned the truck.

I don't get it. AF will flow through the rear lines and core very easily (will do it simply by gravity). The fan blows plenty strong, the servos/diverters work.
 
I have same issue as DennisG, my rear is not blowing hot air. I think it is a problem with the heater core. But I live in TX, so the front is sufficient for most time. If it gets too cold like this past few days, we actually got a wet snow this past Wednesday, it is just taking a little bit longer to heat up using the front only. Would you believe, TX is colder than the Northeast?

There is no coolant flow problem since I have a leak on the return coolant quick connect underneath the passenger seat that has been fixed. When I fixed that, there was plenty of coolant being drained about a little more than 1 gallon or so. You can search for that thread here.

No, there is no restriction on those tee. If there is, I cannot see it. I am not sure how THEFERMENATOR create the restrictor on these tee-s? I have not tried to flush it though.
 
brain fart

Reminds me of a troubleshooting manual for a radar system (1970s); After many pages of possible causes and solutions for a certain problem, the manual writer was frustrated, I suppose.

Listed problem; intermittent blurry image.

Possible cause; demonic influences.:eek:

Solution; pray for Devine guidance, consult an exorsist. :rolleyes5:

I was good at trouble shooting, but not so much any more. Maybe if we were geographically closer, the solution would occur to us after a few drinks. My treat. :D
 
dangerousdave said:
Reminds me of a troubleshooting manual for a radar system (1970s); After many pages of possible causes and solutions for a certain problem, the manual writer was frustrated, I suppose.

Listed problem; intermittent blurry image.

Possible cause; demonic influences.:eek:

Solution; pray for Devine guidance, consult an exorsist. :rolleyes5:

I was good at trouble shooting, but not so much any more. Maybe if we were geographically closer, the solution would occur to us after a few drinks. My treat. :D
Click to expand...

Yeah, I'm totally stumped. Thanks for the offer! I bet we could figure it out! I realize there's only so much one can do via a forum. Oh well, I rarely use the 3rd seat, so it's not like anyone is freezing back there. Maybe I'll experiment some time with that valve.
 
Ya might try changing it's position, switching it over to the other line, maybe before or aft the T's, just another thought.

The 'burb is a large volume of cold air, and ours warms up faster when we run both heaters at the same time. 'Course, having a tank type heater circulating hot water through the entire system at night means instant heat.
Not that it gets that cold here, but my bones like warm better than cold, and I'm going to get one this winter. Maybe today. And one of those stick-on heaters for the oil pan, so the bottom end doesn't get too envious.
 
Nah, the magnetic one sticks out too far, and would fall off on some bump. I don't need too much, and it's easier to plug it in and keep it warm all night.
This one sticks on with silicone adhesive or some such stuff.

Kats 24100 100 Watt 4"x 5" Universal Hot Pad Heater
$20. free ship on amazon
 

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dangerousdave said:
Nah, the magnetic one sticks out too far, and would fall off on some bump. I don't need too much, and it's easier to plug it in and keep it warm all night.
This one sticks on with silicone adhesive or some such stuff.

Kats 24100 100 Watt 4"x 5" Universal Hot Pad Heater
$20. free ship on amazon
Click to expand...

The kind of pad heater in the picture above is what I ised when I lived in Fairbanks, Alaska. I used one on my oil pan, under the battery, and on the trans if it was an auto. I also used a tank type circulation heater. It would circulate the anti-freeze backwards threw the motor and radiator.
 
DieselCash said:
The kind of pad heater in the picture above is what I ised when I lived in Fairbanks, Alaska. I used one on my oil pan, under the battery, and on the trans if it was an auto. I also used a tank type circulation heater. It would circulate the anti-freeze backwards threw the motor and radiator.
Click to expand...

Yup, looking at the circulating tank heater too, maybe put it on a timer to start an hour before launch; 1,000 watt unit for $35. Sweetie is driving it now, and the instant heat would make her HAPPY; better than a diamond!:thumbsup:
 
Yo! Dennis...Suburban heater T fittings and restrictors

I bought a new fitting from NAPA to replace the QD (quick disconnect) POS that the PO had replaced with another OEM POS QD. Supposedly it had the right restriction, but it didn't.

While removing the hose, one of the T fittings (the lower one) broke to pieces, and NOW I understand.

There are 3 restrictors, and all must be in the right position for the two heaters to work right.
One is in the QD, the other two are built into in the T fittings, all 3 are very restrictive, effectively slowing the water flow in all the right places.
The QD's restrictor is maybe 6mm. The restrictors in the Ts are in opposite positions, and are about 4mm.
The hoses front of the Ts are tied down to a support bracket, and the lower one has the restrictor in the rear part of the T.
The top one has the restrictor in the front facing part of the T.

Note that the hose sizes and nipples are different sizes. The hoses, and nipples from the front ( QD and radiator) are 5/8. The side and rear facing hoses and nipples are 3/4.

Strangely, the upper T was great condition, and I even tried to break it. I suspect the PO replaced it.

I Wish I had measured exactly and taken better and more pictures.
I pieced together my own brass T fitting, and made my own restrictor. I have lots of scrap brass, copper, and aluminum pieces from old projects. Not junk, stock inventory (my version).

I also wish I had clamped the heater hose between the T and the aluminum line at the rear of the engine to prevent the shattered pieces of T from going down the pipe. I flushed the chunks out, but prevention would have heen easier. Could have vacuumed the chunks out with the old wet vac.

I also wish I could win the lottery and stop all the evil in the world.


And that diesel was $0.99 / gallon again. Ahh, well...
 

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I should still have a set of those plastic tees out in the shop as they wouldn't work with the DMAX. I had replaced them back in 05 so they aren't that old. Let me know if you want em.
 
OK. Now I'm confused again. I thought it was just going to come down to switching the two lines around that go to the two cores since my rear heat used to work with the current Tee's (they do not have restrictors - I am 100% positive). But, it appears Dave has the same green hose going to the front core -- #2 -- (which I'll assume does not neck down... just like mine). The hose that is currently in the position of "rear core inlet" -- #3 -- does neck down.

So, just to clear things up (for me, anyway) -- according to the numbers in this pic, what sections of the Tee's are supposed to have restrictors?

Ferm... I think you mentioned this above somewhere, but you're 100% positive that those Tee's you have do have restrictors? I just keep coming back to not understanding why everything worked before, and now it doesn't.

Unless, could my restrictors have fallen out? While the engine was out of the truck and everything was disconnected? I mean, are they an actual part of the Tee, or could they come apart?

I really appreciate all the help! Oh, I dream of $.99 diesel, too!!!!

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toddlnrd said:
THEFERMANATOR,
I replaced the tees that you are talking about with NON-factory ones (no restrictors) and my heat works just fine in the front and rear. Maybe I don't know what tees you are talking about. I replaced the ones in the engine compartment, just above the intake manifold on the passenger side.

They crumbled in my hand when I touched them!

Todd
Click to expand...

I made new T's for ours out of I think it was 5/8 x 3/4 pex nipples and a 3/4" copper T. A little solder and done.
 
At 3 and 4, I believe. It was only yesterday, so I'm pretty sure. My Ts have the restrictors cast in the plastic, so I doubt they could fall out. The restrictor at the QD is not attached, and may have come loose, but I can't see how.
Wish I was there to help.
 
dangerousdave said:
At 3 and 4, I believe. It was only yesterday, so I'm pretty sure. My Ts have the restrictors cast in the plastic, so I doubt they could fall out. The restrictor at the QD is not attached, and may have come loose, but I can't see how.
Wish I was there to help.
Click to expand...

Hmmmm. I can understand the restrictor at #4 to balance the system with the restrictor in the QD. I'm assuming my QD has the restrictor (NAPA part, bought about 2 years ago when engine was out).

But, the #3 is confusing. If I add a restrictor to the rear core, I can only guess that it's going to be even less likely to get any flow to it. I would think the restrictor would be in #2?

I don't know????
 
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