Runs hot 190-240 but heater blows cold air

willythec
0

Asked by willythec Jan 16, 2007 at 05:47 PM about the 1995 Pontiac Firebird Base

Question type: Maintenance & Repair

the temp guage goes to 185 then raises to 240 then back to 180. meanwhile the heater is blowing cold air. Then I park it for five minutes, the temp goes down to 180 and stays there and the heater starts blowing warm and hot air.  Someone says the head gasket is blown.  But I have no oil in the water or vica versa. What causes the eingine tempuature gage to fluxuate like this? I have a 3.4 L V6 and runs great for five minutes and the temperature gage goes nuts. Any feed back?
Willy the C.  wcaraveo@eeeveterans.org

19 Answers

tropikalpirate
5,455

The temperature sending unit could be bad. This screws into the top of the engine is inexpensive to replace. That could be why the temp gauge is going up and down so much. For the issue of the heater blowing cold air go to this link: http://www.trustmymechanic.com/auto-repair/25/title-1998-ford-windstar-heater-not-hot.html This tells you how to check to see what the problem is.

5 out of 5 people think this is helpful.
Bryan McIntyre
105

well does water come into the passenger side floor when you turn sharp?

4 out of 4 people think this is helpful.
Jim Morrison
125

my Sunfire did something similar,, turns out that I had the antifreeze to strong

3 out of 3 people think this is helpful.
Josh Scriven
55

Check your coolant, if your car is blowing out cold air when hot it could turn into a serious problem if your low, look under your car for a leak. If you have any antifreeze inside the car it is most likely the heater core

Josh Scriven
55

oh and if your low add coolant!

Chris Hansen
65

you could possibly have air in your cooling system,have you flushed your system lately or change any part of the system? also you could have a bad thermostat.

1 out of 1 people think this is helpful.
Mike85008
160

i have a 3.8 v6 and my temp gauge constantly fluctuates from 185 to nearly 235 then back down again. when i turn on the heater it alternates blowing cold air and hot air with the temp gauge (when the temp is high heater blows cold, when temp is low heater blows hot) i recently changed the water pump and the antifreeze... then i drove 710 miles to phoenix and it made it perfectly fine. but when i got there it started doing the temp fluctuation... so i replaced the thermostat and changed coolant again and it still does it... HELP?

16 out of 16 people think this is helpful.
Jason Zane
3,355

also... did you bleed out the air with the small screws when filling with coolant??? there could be air pockets in the top hose.. could be a heater core leak or airpockets in the heater core lines. how does the water pump sound ??? no unusual noises periodically?

2 out of 2 people think this is helpful.
chadman
0

buy a new thermistat.

Venomist
80

I have a '96 3.8L Firebird and it started doing the same thing today. I was driving and happened to look down and see the temp gauge at a ridiculously high level...turned the heater on and it would blow hot and then cold and back again. Same exact ordeal. I just recently had the radiator, thermostat, and hoses replaced...and had the water pump replaced about a year ago. Any suggestions?

8 out of 8 people think this is helpful.
Ray Goines
25

a lot of times is low on coolet if the heater gets warm one mintue then get cool it is low but if your gauge is going up and down it could be a bad ground most likely it is low

Dustang Willy
55

it sounds like a bad thermostat especially if it breaks stepping on the gas pedal will force the water pump to put pressure on it and force it open causing warm coolant to moveand drop the temp. have u checked engine temp opposed to the radiator? it really sounds like a thermostat issue

Mike Bonnell
6,655

This is what you need to do - IF the thermostat is NOT new do it, it is always the first place to start. Make sure the cooling system is full and air bled off properly. Take it for a short highway trip 10 - 20 miles and see if it starts to do it again. If it seems fine yopu MAY have fixed your problem. Keep an eye on coolant usage and temp fluctuations aftward. If it comes back OR if the thermostat did not fix it you need head gaskets. It is not yet bad enough to effect runability but enough to 'airate' the cooling system with carbon dioxide ( Combustion gases ) - A thermostat is really an aquastat and needs to be in water/coolant to work properly and if set in a air /carbon dioxide setting it will open and close at will. This also relates obviously to the loss of heater function because of the lack of proper thermostat operation and the heater core getting airated. Do not drive this car too much like this. Good luck

2 out of 2 people think this is helpful.
John Saffrahn
15,885

sounds like an air pocket check the coolant level in the radiator (DO NOT OPEN WHEN UNDER PRESSURE----OPENING UNDER PRESSURE=GEYSER OF ANTIFREEZE) check pressure by squeezing top radiator hose usually pressure will fully relieve after being shut off for 20 mins. if ur not sure just let the engine cool completely.

1 out of 1 people think this is helpful.
troll54
20

i have the same problem can you help me changed water pump and thermostat and anti-freeze

2 out of 2 people think this is helpful.
RSS_1TA
80

My only suggestion is and I do not have that decade of a firebird but my mother did and according to her she mentioned to me that she had a vacuum leak due to a check valve permitting vacuum diaghrams to not hold open or close depending if you are speeding up or slowing down and that would add or take away vacuum from the diverter valve to the heater core. Try that on for size and have a looksy there. All that I can think of not seeing the car at hand. One more thing be sure that the vacuum resivor is not cracked and actually holds a vacuum, (that is the supply to opperate all vacumm assisted diverter doors in the cab as well as under hood sensors.)

debbi57
0

My 98 Firebird V6 did the same thing.T hoses to heater core were clogged. Also if I add alot to raditiator I have to bleed it or it runs hot.I still have issues wit it but it runs cooler more & heater works great

Ws6_KiNg
45

i have the exact same problem on my firebird v8 and i changed evrything a new radiator the coolant temp sensor the coolant level sensor new coolant fan motor only thing i got left to check are the hoses and the temperature switch i bled the top hose and all and my waterpumps still good unless the bearings goin bad but i recommend checking your top radiator hose un screw it enough to leak out the air til wat squirts out if that doesnt work make sure ur radiator is filled properly and dont put water in your radiator breather hole thats just for when it gets hot the fluids have somewhere to go and not fly out like a geyser but if that doesnt work put a coolant temp switch on which is under the thermostat ull have to go under the car to get to it and if that dont work put in a temp switch aka temperature sending unit and if that dont work put bigger stuff like a radiator ...hoses...water pump and so on

1 out of 1 people think this is helpful.
Tyler Sutton
55

my v8 has the same problem its just the way the block was built the high horse powered motors need more heat in them to run better just not a whole lot should run any where between half and three quarters

3 out of 3 people think this is helpful.

Your Answer

Add photo

Related Questions

  • 1995 firebird blows cold air on feet , but not out of dashboard. WHY? 3 answers

    1995 firebird blows cold air on feet , but not out of dashboard. WHY?

    1995 Pontiac Firebird Base

    -

    Maintenance & Repair

  • My Firebird still running hot, on and off. 5 answers

    I left off a lot of information from my previous question so let me add some to it. I have a '95 Firebird with a Pontiac 3.4 L V-6 engine. The person that donated the car to our Non-profit said the he...

    1995 Pontiac Firebird Base

    -

    Maintenance & Repair

  • A few symptoms but from what ive read im not sure where to look 5 answers

    So my wife has a 2002 Firebird 3800 series V6. There are a few symptoms that worry me. First, the car runs hot, even if i have just filled it with coolant. To go along with that, the coolant just d...

    Pontiac Firebird

    -

    Maintenance & Repair

  • after car warms up it runs badly what could cause this 8 answers

    When I first start my car up in the morning it runs great for about 5-10 mins or until warm. After this it starts to run rough and backfire at low rpms. At high rpms it seems to be missing and has l...

    1994 Pontiac Firebird Formula

    -

    Maintenance & Repair

  • Heater not getting hot 9 answers

    I have a 2005 pontiac grand prix. Heater fan works, but blows cool air. We replaced the thermostat but that didn't make a difference. What else could be wrong besides the heater core? Is there any...

    2005 Pontiac Grand Prix GT

    -

    Maintenance & Repair

Firebird
Looking for a Used Firebird in your area?
CarGurus has 853 nationwide Firebird listings starting at $2,495.
ZIP:

Search Pontiac Firebird Questions

Pontiac Firebird Experts

#1 dandyoun
dandyoun
Reputation 650
#2 Samuel Moore
Samuel Moore
Reputation 620
#3 John Saffrahn
John Saffrahn
Reputation 520
View All

Related Models For Sale

Used Chevrolet Camaro"
682 Great Deals out of 28,206 listings starting at $2,399
Used Ford Mustang"
1,084 Great Deals out of 24,290 listings starting at $950
Used Chevrolet Corvette"
384 Great Deals out of 10,585 listings starting at $3,450
Used Ford Mustang SVT Cobra"
16 Great Deals out of 291 listings starting at $5,500
Used Pontiac Grand Prix"
228 Great Deals out of 5,651 listings starting at $1,500
Used Chevrolet Monte Carlo"
62 Great Deals out of 2,617 listings starting at $1,595
Used Jeep Wrangler"
920 Great Deals out of 42,840 listings starting at $1,800
Used Pontiac Grand Am"
58 Great Deals out of 2,691 listings starting at $890
Used Ford F-150"
2,485 Great Deals out of 177,299 listings starting at $1,495

Used Cars For Sale

2002 Pontiac Firebird Base For Sale
34 listings starting at $3,000
2001 Pontiac Firebird Base For Sale
41 listings starting at $2,988
2000 Pontiac Firebird Base For Sale
40 listings starting at $2,495