No Heat-Thinking it's the T-stat?

Heater core is plugged. Flush it out both ways.

Tom C.

I'll disagree. Open t stat. Had the exact same symptoms. If it builds heat when idling and stationary, it isn't a plugged core. When you get moving, the coolant is over cooled from the moving air.

Sounds just like the problem I have. I flushed the heater core and every thing was good. Now the heater core is getting more crap in it. I know I'm going to have to flush it again. I can't believe the crap that came out!!

Randy

I did forget to mention, that when the temp. went up on the diagnostic, in my garage, the temperature gauge itself went up, as well! Of course, all summer it didn't seem to work, but I really didn't idle it too much. And, I just thought that the gauge simply didn't work (fuse, or something?). So now, I know the gauge DOES work, that's why I'm still leaning towards the t-stat. Possibly, maybe a little of both?

I'm editing this, to ask how DOES one flush the heater core? My buddy said it's simple, but I know I can't get to the connections by the firewall. Do you take off the heater hoses by the water pump? If so, then what?

John [b]

94 Roadmaster Wagon wrote:

I'm editing this, to ask how DOES one flush the heater core? My buddy said it's simple, but I know I can't get to the connections by the firewall. Do you take off the heater hoses by the water pump? If so, then what?
John [b]

You need to get into the two hoses that go to your heater core. Someplace you can disconnect or cut the hose and put a coupling in after your done. You can buy an adapter that allows you to connect a garden hose directly to the heater hose. Flush one way and then reverse and flush the other. You will be surprised by all the stuff that comes out.

Tom C.

Maybe you put in a wrong T-stat? (to cool) I bought one at Auto zone a while ago and it turned out to have a different temp rating than it said on the box. (as you said, your temp gauge is working a little)
Pete

Dutch Pete wrote:

Maybe you put in a wrong T-stat? (to cool) I bought one at Auto zone a while ago and it turned out to have a different temp rating than it said on the box. (as you said, your temp gauge is working a little)
Pete

You know, that could be right! I do know after looking up from the 'big three' (Autozone, Advanced, and NAPA), that most do stock a 160 degree t-stat as an 'option'. Maybe when I bought this one, that's what I got! I believe it was warm out when I changed it, so I didn't need the heat. And, when I drove down the road, it cooled down from 190 to 165 and stayed there. So, maybe it IS a 160 degree stat!

So that brings me to another question. I made sure I bought a 180 degree heavy duty stat today, but no one had a 195 degree. The 180 degree stat will be good enough, right? Rock Auto has the 195 degree, but it's only a 'regular' stat, not the 'premium' one. I can tell the one I bought is better than a 'standard' one, just by looking at it. I got it at Advanced, and it was like $15.00, so it better be good! I know NAPA had some 'premium' ones, but they were charging over $20 for them!! O'Reillys were charging over $30.00 for some!! HOLY COW!!

What do you guys run? Like I said, I can only find 195 degree stats at Rock Auto. I'm hoping that the 180 degree one I bought will give me enough heat.

John[b]

180 is stock for the LT1 cars. Make sure you got the right one (no gasket, just o ring), and that you put it in the right way.

You can easily flush the heater core by disconnecting the two small hoses that connect to the passenger side of the water pump. Then take a garden hose on low pressure and flush in each hose back and forth until it burps something out.

For what it's worth, on my 9C1 I was having to flush the heater core every year for a number of years.

If you then need more heat, drill out the stupid plastic flow restrictor. My 96 RMW brand new would not thaw the windshield off, I drilled that restrictor out larger and then it heated like crazy!

I'll bet on the core being plugged, just like Sherlock I flush my cores each fall on the LT1 cars. When the car is hot, feel the hoses going to the heater core. If one is hot and the other isn't, the core is plugged up.

jayoldschool wrote:

180 is stock for the LT1 cars. Make sure you got the right one (no gasket, just o ring), and that you put it in the right way.

What is the 'right way'? Is it where the spring is on the bottom side, and the 'spaceship' looking top is on top?

Also, do you need any RTV around the base, since it's only that little rubber o ring?

Thanks,
John[b]

Deadmanonduty wrote:

If you then need more heat, drill out the stupid plastic flow restrictor. My 96 RMW brand new would not thaw the windshield off, I drilled that restrictor out larger and then it heated like crazy!

Where is this restrictor at? I might as well do that too!

John[b]

I would not do that to the restrictor, that is there for a purpose. That's not your problem.


Tom C.

T-stat looks like an arrow place it pointing in the direction of the coolant flow.

scoffman wrote:

T-stat looks like an arrow place it pointing in the direction of the coolant flow.

So then, which way IS the coolant flow? Does it come through the radiator, through the hose, or does it come from the engine? So again, should the spring part be on the bottom, and the 'spaceship' looking top be on top?

John[b]

94 Roadmaster Wagon wrote:

Deadmanonduty wrote:

If you then need more heat, drill out the stupid plastic flow restrictor. My 96 RMW brand new would not thaw the windshield off, I drilled that restrictor out larger and then it heated like crazy!

Where is this restrictor at? I might as well do that too!

John[b]

Its a plastic piece in the hoses. Guys say if you remove it, you can burst your heater core, so I just drilled mine a little bigger. I have run it like this almost 200,000 miles with no trouble in a couple different cars........I like heat in Northern Wisconsin!

Many moons ago I had a 75 Colony Park with heating issues. Heater inlet was warm, outlet was cool. I tried a garden hose to backflush and it only moved a dirty trickle.

Figuring I had to replace the core and therefore had nothing to lose, I hooked it up to a fire pump. Starting with a low pressure, I flushed until clear, then snuck up the pressure another 5 psi. When that was clear, I snuck it up a bit more, and so forth. I think I was up over 100psi when increasing the pressure no longer produced new crap. Surprisingly, the thing actually held at those pressures! I was sure it would burst eventually.

When I was done, the flow rate through the core was greatly increased -- I don't think it would noticeably reduce the flow from a garden hose. And the heat output was fantastic!

I really don't think the restrictor is there to prevent the heater core from bursting. However, with the reverse-flow design of the LT1 cooling system, it may play some sort of role in the overall engine cooling flow rates.

94 Roadmaster Wagon wrote:

scoffman wrote:

T-stat looks like an arrow place it pointing in the direction of the coolant flow.

So then, which way IS the coolant flow? Does it come through the radiator, through the hose, or does it come from the engine? So again, should the spring part be on the bottom, and the 'spaceship' looking top be on top?

John[b]

Sorry I'm one of them TBI guy's so can't say which way the coolant flows on a LT1. Mine is going to flow out of the engine and back into the rad. The t-stat housing is on top of the front of the engine so. . .I'm going to place the t-stat in where it looks like it's pointing up.

Mayhaps one of them ther LT1 guru's could chime in on the flow direction. It is suppose to be reverse flow from a normal 5.7 though, if that helps ya any.

This may help.

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Randy

It looks like the spring part sits down in the housing. I have two LT1 cars and they need to have the heater core flushed each season. It's a pain because of the coolant dump.

Randy

yakko wrote:

This may help.

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Randy

It also shows a gasket! I was under the impression that there wasn't any, due to the "O Ring" around the thermostat? When I put it together, it was seeping just a little bit, on the front side. So, I drained it back down, took it apart, and just put a thin layer of RTV around it. No more seeping!

John[b]

There isn't a gasket.