Got a 95 z28 all stock except the flowmaster exhaust and my stereo system. Engine runs around 180 degrees and my heat is barely warm. I've flushed the heater core replaced the thermostat and still it's not getting any better. A/c is freezing cold. And I forgot to mention if I leave it running sitting still it'll warm up to around 200-210 degrees and the hear starts working but once I get moving the motor cools bam down to 180 and heat cools back down to dang near the feeling of a/c. Anyone got any ideas to what it is?

 

Your heater core may be clogged beyond what flushing can help. It may need to be completely replaced. It is also possible that the flow control valve on the lower outlet hose has failed/clogged, preventing the flow of coolant to the heater core.

 

I agree.... may flush out may not..... backflush it and see what happens... Maybe a blend door possibly part open? if the heat is getting that cool

 

how would i go about testing that flow control valve to be clogged??? imma younger mechanic so im not a pro at heating or a/c

also is it normal for it to run at 180 degrees all the time? i thought it was supposed to keep warm around 210 or so even while moving down the road

 

it heats up when idling

moving down the road, especially highway cruising with all that extra air flow, the temp will stay cooler.

 

Sounds like it could possibly have a cooler thermostat in it but the fans aren't programmed for it. You may also want to make sure the ducts in the car are working like they are supposed.

First check and make sure you don't have leaves or other debris in the heater box and second make sure the vacuum lines that operate the system are working.

 

Oem thermostat is 180 that's what I got in it. I'll check the heater box and I'll see what I can do to check those vacuum lines

 

I would start with haveing the a/c in the cool setting, . move the mode indicator into each mode, Floor,floor/dash,dash,defrost, ect.... Make sure the blend doors are moving correctly and not sticking in a spot. use your senses to listen and feel if air is coming out of vents that should not be blowing air. if everything seems to be working properly then move to the next area.

to check the control head vacuum hoses i use a squirt bottle that has a hose from the bottle to the spuirter. The reason is getting the bottle to fit under the dash and to spray is hard. use a soapy water solution. BEFORE i spray anything down i do a feel and hearing test. i also use a stethiscope to narrow it down. But if not then... use the water bottle.

You said you flushed the system out already did anything othere than water come out to give you the impression there may be something preventing flow in the heater core system or a hose? did you remove the 2 hoses and flush them out as well?

 

That's all great, but the temperature door is not vacuum controlled-it is controlled by a cable from the temp ****. Vacuum controls the modes and air direction.

I'd personally start with flushing the hoses and core from the water pump end and then re-evaluate.

 

Well I looked around in the heater box the best I could didn't see anything blocking any air flow like leaves or dirt it's cleaner in the heater box than my floor board is and I wash it around twice a week lol. Didn't notice any vacuum leaks so I'll try testing each mode on the a/c control. What difference should I notice from max mode to a/c mode? I've never really noticed any difference there in what vents blow and what ones don't.

Last year when I flushed my entire cooling system all kinds of black tar looking stuff was coming out of the Heatercore and the hoses. Maybe I should just replace the hoses and heatercore as it's a 95 and they've never been replaced. Anyone know if oriely's heatercore is any different than a gm one as there's almost a 200$ difference in price?

 

As noted (sort of) in a post above, there's a flow limiter orifice in the heater hose. Could easily be plugged up if you had a lot of black gunk in the heater. I'd follow Rob/Shoebox's suggestion before buying new parts.

Look at part 13 in this diagram.... courtesy of Shoebox:

http://shbox.com/1/heater_hoses.jpg

 

that hose is running straight off the radiator right?

or is that from the water pump? i've also heard replace my water pump could help as well since i do have 153k miles on it.. but i figure for a 95 thats not too bad and its in great condition the t-tops dont leak but thats all recommendations from lower end techs at my job. like i said before im no master mechanic im just now learning alot more about all this stuff as i go and i dont believe in doing stuff all riged up either, i'd rather spend cash to have it done right if thats a must

also i have an important question... is my primary fan on my radiator supposed to start spinning as soon as the car is cranked even if its cold? like as if i left it sitting over night because the primary fan is always on in my car and its not straight wired.. if the motor is running so is it.

another thing, the lady that owned the car before me told me that she had the radiator replaced soon before she traded it in at the dealership i found it at.. anyone think they may have messed with the settings in my computer for the fans?

 

The radiator is not shown in that diagram. The heater hoses come off the water pump.

Seems like you are dead set on spending a lot of cash to solve the problem, so good luck. Checking parts before replacing them at random would not be my definition of "all riged up" (whatever "riged" means).... but that's just me.

 

If that flow limiter is removed would it do anything except possibly make the heater less efficient?

 

no i just know i've already flushed it before and if imma have to keep flushing it every year for the winter then why not just replace all the hoses and the heater core instead of paying for gallons of coolant every year to flush my system lol. but im young and dumb i suppose thats why im here for your advice bro. i dont mean any harm by anything i've said im just doing the best i can at the moment