hot motor,cold radiator,no heat

[scott29]

I have a 95 lumina with a 3.1. When I got it the fans would not come on. I changed the sensor and checked the relays and fuses, but everything checked out o.k. They still did not run, so I ran new wires thru a new relay, so now the fans come on with the ignition in run. About a week ago it got cold outside and realized I have no heat. The inside fan works fine. A couple of days ago the temp guage flew up to the 260 mark and the motor lost power. I shut it off right away. The motor runs fine still, I replaced the thermostat, pulled off the water pump and checked it, the impeller is fine. I filled it back up and let it idle a while and the temp flew up to half way and slowly crept up to about 240. I spent some time with the bleeder screws, opening them till it was a constant stream out of both bleeders. But to no avail, the temp still climbs up and wont come back down unless you shut it off for a while. Anyone have any problems like this? I would much appreciate some advice, because I'm lost. Thanks, Scott29.

[Blue Bowtie]

Welcome Aboard!

It seems that it might have some restriction, either in the radiator or within the engine. Since clogging of ALL the cylinder head/deck holes is rare, I'm guessing the radiator may need to be removed and checked for blockage.

[mtsz52784]

sorry just wanted to repost to see if it is the same as above.....



Hey quick question guys first time poster long time looker... i have a 95 Lumina and all of a sudden when i started the car one day(cold) the temp went all the way up to 260 and stayed hot until i came to a light and the heater is blowing cold air(about 30 seconds) i then took off and the temp dropped to a little less then normal and also started blowing hot air... after driving a little more i noticed that the temp is up and down and so is the heat blowing out of it (hot then cold then back). after about 30 min driving the engine will finally totally heat up and blows out hot air (less extreme fluctuating). I took it to a well trusted and used mechanic who replaced the T-stat last year. i told him what was going on and he bled the system of air. i got it back and he was still confused so he replaced the t-stat (free of charge) and it is still going on.... he started looking into it more and called around to different places and he doesnt do head gaskets but both the people he talked to said it would be the head gasket. he said he pulled a couple plugs and there was no anti-freeze in the oil. SO i'm wondering if this sounds like the intake manifold gasket as described in other threads... i did bring it up to my mechanic about being the intake manifold gasket... he kind of looked into it and i think shrugged it off... ANY HELP PLEASE SO I CAN DO IT THIS WEEKEND IF NEEDED!!! Thanks Matt

[coolcam]

hey!I am having similar problem.Temp guage goes all the way up and no heat then back down and has heat.It keeps doing this up then down again.Fluid level is fine.If you get an answer let me know.Thanks

[mtsz52784]

ill let you know after monday because i bought the gasket kit for the intake manifold at autozone for $85 and will be doing it this weekend.

[richtazz]

Unless the car was overheated, I doubt seriously it's a head gasket. 95% of these cars only need intake gaskets (if not overheated), but mechanics get paid more for doing head gaskets. A compression test, and cooling system pressure test would verify. If you pressurize the cooling system, you should be able to hear where the pressure is bleeding off. If you suspect it's head gaskets, removing the spark plugs (part of doing a compression test anyway) will assist in hearing the leak in the cylinder if present. I'm almost positive AutoZone offers a cooling system pressure tester in their free tool loan program.

[4evrbad]

I have not had this problem with my lumina but I used to own a Grand Am with this problem, after many parts and diagnosis It ended up being a relay.

[soopacee]

my '97 was going through the same thing........replaced the thermostat....NADA......the car never overheated.....but the temp gauge went all the way up to hot, but never stalled......IT WAS a Blown Head Gasket

so be careful

[mtsz52784]

well i will find out tomorrow i have a buddy that works for GM and will fix it tomorrow night...

[coolcam]

well mtsz,what have you found out.anxiously awaiting your update.

[mtsz52784]

As you can see that the intake manifold gaskets were crap... this is just a couple pictures of the rear intakes... after seeing this we decided not to do the head gaskets because this was pretty significant... WRONG... after getting it done everything worked great last night but the real test was this morning when everything was cold... Temp still went to 260 and not blowing hot air... talked to my mechanic again this morning and we will be doing the whole thing over again plus heads... we know the temp on the dash is right because we plugged the car into the computer and it was showing correct. SO heads and intake again this saturday.

[richtazz]

Did he replace the thermostat and bleed the cooling system of air? A head gasket will not cause the temp to spike when cold, but air trapped in the cooling system will. Before you tear that engine down again, do a compression and cooling system leak down test. I seriously doubt by your symptoms that it's a head gasket (not impossible, but highly improbable). The temp sensor for the guage is in the rear head, the temp sensor for the computer is in the intake just below the t-stat housing. This is the area that the air pocket will form if the cooling system isn't bled of air properly. The guage will peg when the sensor is not immersed in coolant, and the ECT will show it's overheating as well if there is air in the system around it. Many people, myself included, will drill a 1/8" diameter hole in the t-stat flange to allow the air to escape while filling the coolant.

[mtsz52784]

yes he did check the tstat, and the cooling system wasbled fully and properly, he has been a mechanic for gm for a bit so i do believe he know what he is talking about, also because he is a good friend he is not charging for labor either... so i doubt that he really want to tear it down and put it back together again... ALSO again after 2 days of driving the temp is still staying at 260 and no hot air out of the vents... and also now showing low coolant, and when he first started to tear down he did say the rear head was leaking but didnt think it needed to be replaced after seeing the intake... anyhelp appreciated

[Lumina827]

I can't believe someone is going through the exact thing I am with my 1997 Chevy Lumina! Only thing I have not heard you mention is the engine lobbing when you mash the accelerator. I just got home from replacing the thermostat ( which is a job and a half!....but do alble) to no avail. patiently awaiting an update.

[mtsz52784]

OK THE LONG AWAITED UPDATE....Lumina 827 I did forget to mention that when i hit the gas the engine does bog down... but here we go with more pics... So after last Monday (presidents day) of changing the intake manifold gaskets and driving home everything was good... the real test was the next morning, so i start to drive and it is doing the same exact thing... so we decide that it has to be a head gasket, so yesterday (saturday) i take it down to the shop where my friends (1 GM mechanic & 1 NY State mechanic) start taking it apart and ii just bring breakfast because they work faster without me getting in the way... so we start at 8:30 and around 10:30~11:00 we get to the head gaskets and notice that cylinder 1 (if you look at the engine from the front of the car it would be the farthest left on the back side of the engine) the top of the piston is clean and sure enough right next to cylinder 1 there is a crack in the head gasket about 1/4" to 1/2" long... so what was happening that coolant was getting into #1 and when spark was there the coolant would clean it...SO it was a head gasket and it took us to 4:30 to get everything done... including changing the starter because as long as we were down there and i believe it was original we might as well change it...DO NOT get the felpro gaskets for the intake manifold, because only after 1 week when we took them off the 4 (yes all 4) where coolant flows through the gaskets looked like sh!t because the rubber was coming off the metal... i stuck with a dealership intake which is better constructed and fit better too... the head gaskets from felpro are fine... ok here are some pictures... ALSO ask me any questions!!!