TheExaminer

....to warm up on a cold morning? I also have two V6's (98 Camaro 3.8 and 07 Mustang 4.0) and by the time I'm 8 miles down the road I'm turning the heat down on them because it's too hot. But that big 350 in my Formula? Nooooooo! It takes that thing forever to warm up, and even when it gets to its warmest, it keeps you basically comfortable, but never gets hot enough to where you feel like you need to cut it back some. All three cars run at about the same operating temp once warmed up, 180-200ish or so. I know what you're thinking, and yes, I have a 195 therm that's only 6 months old, and a heater core that's about 10 months old. My coolant level is good, I fixed my bad hoses/leaks, have new coolant, and did a radiator/coolant flush last summer, and another water flush with knock sensor/block plugs removed to clean out more of the crap a couple weeks back while I was winterizing it. Now my fan only blows at about 60% original speed, so it's seen its better days, but that's not the issue. The air temp coming out is not hot, doesn't matter the air speed. I just went through the controller and fixed the main switch and vacuum wheel too, and they seem to work fine now. The blend door also seems to be moved all the way over into position, but maybe it's fooling me, idk. So WHY? What else is there other than the components I've already mentioned?

eseibel67

A 195* stat should make enough heat to soften your rubber boots. WIth everything you've done, there are only a few possibilities left. You said the blend door is going full hot, so that's good. I think you have a coolant restriction or an air bubble in the system. The heater core is in a high position and can trap air. Best way to test is when the engine is at full temp, feel both heater hoses running through the firewall. Both should be too hot to hold for more than a few seconds.

If you suspect air in the system, you can get the air bubble out of the heater core by running the engine with the rad cap off (starting when it's cool enough to remove safely of course), and jacking the front passenger side of the car up as high as your jack will go. Park the car with a nose up attitude in the driveway before you even start this for ven higher probability of good results.

If both heater hoses are cold, a possible culprit may be the heater bypass valve located near the front of the pass side valve cover. If this thing if stuck in bypass you will never get heat. Test by checking temp of the downstream hoses with the A/C both on and off.

TheExaminer

Ok, I can try some of those things, but that reminds me--I forgot to add that I have a new heater bypass valve too! LOL.... And the vacuum at the valve is off during heat, and on during cool--which is what I think it's supposed to do because when it's on, coolant is diverted away from the htc toward the oil cooler. As far as I recall, both htc hoses were warm when I checked them the other day. This car has always done this since I first got it last December. Although I will add that the PO had a 160 therm in there that I took out last June. Even with all these changes I've made, the heat STILL does not get hot. Maybe the new 195 therm was bad out of the box? I just don't know.....but I think I might pull that kick panel off again and make doubly sure the blend door really is closing all the way.

rusty vango

did you replace your heater core with one of those POS aluminum ones? if you did ,theres your answer as to why the heat isn't good enough.

TheExaminer

IDK. That was when I first got the car and didn't know how to do much. I had to pay someone to do it, so I don't know what he used. I've done pretty much all my own work since then, and if I had it to do over, I'd have done this myself too even though the guy who did it was a good mechanic. At first I just had no choice, I didn't know much and it had to be done.

rusty vango

you can tell if its one of those aluminum ones easy enough. look at where the heater hoses connect at the firewall. if you see a silvery metal, well dammit, however if you see brass .at least you got the proper core.

TheExaminer

Yeah, I'm willing to bet money it's aluminum. That's what most parts stores carry now. Are OE's brass then? But don't most new cars use aluminum htc's? Would it really make that much difference? My 07 is hot enough to burn your hand, I've never checked to see what the core is made of.

rusty vango

yes, most newer cars come with aluminum or plastic heater cores. our cars came originally with a copper /brass heater core. I can no longer find the real deal heater cores. they aren't being manufactured any longer. for a car designed for one, they are ok. but installing one of those in our cars results in less heat for some reason.

TheExaminer

Interesting, I wonder why that is? Doesn't seem like the car would care what the core is made of when the coolant is 180-200 deg. That's about the same temp my other cars run at, so it can't be the core itself. There may be a difference in air passages inside the hvac or something.

eseibel67

The cheapo aluminum heater cores are crappy and probably won't last very long. Although the water passages might be smaller, they will still transfer heat from the water into the air so I don't think that's your problem here.

TheExaminer

Then what? Air bubbles? That seems unlikely, but possible I guess. I don't think the new therm was faulty, because it doesn't take long for the engine itself to reach operating temp, it's just that somehow the heat never makes it into the cabin, or at least, never gets as hot as it should--just sort of moderately warm.

rusty vango

they are quite a bit smaller when a side to side comparison is made. just for S&Gs I measured the amount of coolant each holds. the aluminum one is 18 OZ while the bigger brass one is 32. this MAY be why they make puny heat.

jaybdaboat

I née to replace my heater core should be doing it today. Where should I get it?

rusty vango

you are better off having your OEM core repaired. as mentioned, the replacement cores don't cut it.

jaybdaboat

I don't know a place around me that will do that for a reasonable amount. Most shops tell me 350-500 just to replace it.

rusty vango

you don't need them to replace it. you only need them to repair your OEM core. as far as the R&R its quite easy,anyone can do it. now as far as no body will repair it. you mean there are NO radiator shops any where around you??

jaybdaboat

I never said there aren't any shops that I couldn't I said I didn't know of any. It's not that easy with no tools and it's 2 degrees outside with no garage. Those prices were just to replace it with another heater core not fix my current.

rusty vango

understood, well on the one hand $500 for a completely underwhelming repair is stupid .to say the least.good luck