Hey guys.....well I'm hoping that my T-Stat went bad, and that's why I'm not getting much heat. I live in Michigan, and if I don't get this fixed soon, ima be an icicle lol. What would be the best temperature T-Stat to buy for the winter? Thanks!

 

I'm running my 160 without that much problem but if you like, try going back to the stock 195. Next thing to check is the heater control valve followed by the heater core.

 

do your windows get fooged up at all? if so thats a sign that your heater core is going out. mine wasnt that hard to replace but was told that the later year 3rd gens are a pain in the a$$

 

Where I live I put the original 192*-195* in winter, and you're north and more colder than me..
***Also this time of year I use a light 5w30synthetic motor oil, to prevent "gelling" of the oil and hard starting.***

*Make sure you have enough anti-freeze, get a "specific gravity" tester.(For me, the "Prestone" one with the needle is easiest to read)
*See if the top radiator hose gets "hard" meaning your cooling system is building pressure like it should. If it has a leak, or coolant gets low your heat won't work as good.
*Feel the hoses on both sides of your "heater control valve", if they're NOT the same temp after warm with the heat on, then it's not working.
*If all of these are good replace the thermostat.

(I have to check the wife's car tomorrow for the same thing, but its like "7*" TONIGHT!!
**So I'll probably slip a piece of cardboard between the A/C condensor and the radiator to limit air passing through the radiator and keep it warmer...

 

If your running temperature comes up and holds approximately at the thermostat temp then the stat is not the problem.

"No heat" situations are usually becuase of a stuck heater bypass valve (used on most fuel injected V8 GM engines of that era) or the heater core itself has become internally plugged with coolant schmutz (often from a neglected coolant system).

They bypass valve is a plastic thing with a vacuum-operated solenoid on the top of it patched into the heater coolant hose lines. It's supplied vacuum any time the HVAC control is pushed all the way to "COLD" which closes the valve and diverts coolant around the heater core and through a separate coolant bypass hose. Otherwise, no vacuum and the valve is supposed to be open, allowing coolant to flow through the heater core.

 

If the lever is all the way too hot it sounds like a heater core. If you have more than 125,000 and poorley maintained the cooling sys, it is scale build up. take a temp reading at the heater hoses, they should be close to the same with the fan off, If there is a 25 degree or more difference, its shot. You can "power flush it". Remove the hoses, and with a garden hoses blow thru each way, then if avaliable fill core, then blow with compressed air. It has worked on many cars and I never damaged a single heater core.
good luck.

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Funny I was just about to post the same topic, my 88 has no heat at all my engine never seems to heat up though, it barely breaks 100 degrees unless its been running for like an hour, I've also heard that if the heater hoses are hooked up backwards the heat will suck. Any truth to that?

 

No the heater core does not care which way the coolant runs thru it. Sounds like you need a stat, or a restriction of air flow thru the rad. You can do this with a thin picece of aluminum sheet, maybe .018 thick. Block off the airflow thru the rad with the sheet, dont cover more than 60 percent of it. I`d try a stat first though.

"get a shaker and put the machine up for the winter"

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The bypass was the problem on my Formula a couple of years back. Boy was I glad it wasn't the heater core!

 

Yea, a new stat was the first thing I tried when I first got the car years ago, not fun and no change in the heat, one of the bolts broke and my drivers side fender ended up with a perfect indent of a combination wrench in it

 

Same here. Damon is right on the money. Mine was doing the same thing with regard to barely any heat coming out of the heater. Tapped on the bypass with wrench and voila - heat! Mine was probably slightly stuck and the tapping was enough to loosen it up and get it functioning again.

 

Alright well I replaced my HCV and thermostat last week. I put in a 195* t-stat. That didn't fix it, although it made it a little bit warm. For some reason, when I keep it on defrost, the drivers side is always warmer than the passanger side. hmm?

A couple days after, I left my dome light on , so I opened my hood to jump my car. I noticed that almost all my coolant was gone. I was like WTF. So I replaced it all and tightened up the thermostat housing (which I believe was the cause of this). Now it doesn't really leak anymore but my car runs MUCH cooler. Before it always ran around 160. Now it always runs around 135-150.......hmmmm.....

I'm a human icicle when I drive. I really don't know what else to try, because last night when my car was warmed up to operating temp and heater was on, I felt the 2 hoses going from the HCV to the firewall....and both were hot and the same temperature......so wTF!!! ahh any input would be appreciated.. thanks

 

Runnign extremely low on coolant can definitely cause some strange behavior at the heater- usually less heat, not more. Engine gets hot but there's not enough coolant to carry the heat away (to the radiator or the heater core).

Your temp should stay right around the thermostat operating temp on cold days and not move much once the engine is fully warmed up (on hot days it will keep going up until the fans kick in and bring it back down when driving at slow speeds when little air is moving through the radiator).

Something sounds a little wacky here. With good coolant level and a fresh stat you should hold a 195* operating temp at the engine (unless the gague is reading wrong). Just to make sure the HCV isn't screwing you up unplug the vacuum line going to it (that will leave it full-open and allow full coolant flow to the heater core). If that doesn't give you heat then almost certainly you have at least a partially clogged heater core.

Still, not running at the stat's 195* opening temp troubles me.... 195* on a stock F-body gague should be just a smidge over the little hash mark half way between the 100* and 220* lines.

 

Hey thanks Damon,

Is the Vacuum line the tiny black one going to the HCV? Sorry, I'm still a bit of a newbie