I've own'd my car for nearly 3 years now, and it has always had the troubles of running hot. Today while driving, my gauge read 240*! It may not truly be that hot, but I know its up there because the performance was lacking. Here's the deal:

I live in Phoenix, AZ, and its over 100* today. I was also in stop-go trafic, with the A/C running full blast.

Within the last 6mts, I have replaced: water pump, radiator, 195* thermostat, and cap. I've done a good back flush, and top'd it with 50/50 antifreeze/water. I've made sure the fan works, the air damn is in great shape, nothing is blocking the radiator, and I've even installed an extra fan in front of the radiator to try and help. (Yes, the fan is turning the proper direction, and is rig'd up to a thermo switch.)

What could be the problem? What am I overlooking?

Thanks

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Rob
'86 TA 305 TPI
Gutted MAF, Ported Plenum
TB Bypass, Home made Cold Air Intake,
Edelbrock T.E.S.

 

Forgot to add: my timing is set at 10*, runs the best there. Before it was at like 5*, ran super hot, and major loss of power.

 

Anyone? I don't want to blow up my toy, I gotta cool this thing down.

 

You could try using a 70/30 mix of water/antifreeze, see if that helps... but Im not sure thats it.

Are you positive the gauge inside the car is reading correctly? Recently, mine stopped working... so I was looking for a replacement, and they changed the style, which would require a different connector. So, I didnt change it and then one day the gauge started working again! It wasnt the gauge in the car either, it was the sender, I checked everything else. I dont trust my temp reading much anymore...

 

I would tend to think the gauge sender is messing up or maybe the wire is grounding out somehow on something-if that wire grounds out the gauge will peg out at 240 or higher. Also I think almost any car's performance will suffer in a 100* temperature-both my cars get sluggish when it gets that hot here in Florida.
As a point of comparison, my engine had a major overheat once, when the water pump/alt belt flew off on the expressway and I didn't have the A/C compressor belt on. Believe me, that engine sure let me know it, with a lot of knocking and sputtering plus a good amount of steam pouring out from under the hood with the coolant bottle overflowing.

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D.R. Stevens
1984 Trans Am 305HO L69
1991 Firebird 305 L03

 

IM HAVING THE EXACT SAME PROBLEM and i did all the same stuff you did so my dad's mechanic is just gonna rebuild the engine and work from there. Although i think its the pulleys.

 

Arizona .... go to a 160 thermo and a fan switch and maybe upgrade to dual fans.

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1989 GTA 350 TPI - T-tops, dual cats, 9-Bolt aussie 3.27
1992 RS 305 TBI - T-tops, T-5, 3.08 - Sold

 

A lower temp thermostat will not cure a cooling problem. His car is running 240, the thermostat is already open all the way no matter what temp thermostat it is.

 

Pour a bottle of waterwetter in the radiator. It will drop the temp a little and should get it back down to 210° to 220°.
That's just a quick fix though.
Sounds like something is wacky somewhere. Maybe your thermo is not opening up all the way.
Also look to see if your bottom radiator hose is colapsing.
Race the engine a few times and look at the bottom hose.

 

Thanks for everyone's advice. I agree, Its probably a bad sending unit. I do admit, the car did not puke all over when I got home, although the gauge would make you think otherwise. I do agree, dual fans, and some water-wetter will diffinatly help.

What years came with dual fans, I suppose this would be a direct "bolt-in" replacement. I shouldn't have to mod anything correct.

 

Do you have a TBI car?

Anyway, I think you need more timing because your balancer has slipped some, here's my reasoning...

If you were at 5* BTDC, and you have a TBI, then you'd be 5* advanced over stock, if you have a TPI car, you're just 1* retarded from stock, and regardless, going from 5* advanced over stock timing (if TBI) or from 1* retarded form stock to an additional 5*, should not have had any impact on your temps...unless you were running severly retarded before...or, you're getting NO advance.

So I guess I'm leaning towards timing not correct due to a slipped balancer, or the advance is not working properly...based on you saying adding in another 5*'s BTDC helped.

 

I have a 305 TPI. I've replaced the balancer about 1 year ago, because it came apart. Once I noticed my timing at 5*, I replaced the timing chain, this was about 3 months ago. So, I should be accuratly at 10* base timing.

 

When I was your neighbor in Glendale I noticed a kind of phenomenon about heat. Madmax is correct logically about not making any difference what temp stat your running since you car is already at 240° ....except in Phoenix.

195° is too hot anywhere and WAY to hot for Phoenix. This is only place I would say you must run a 160° at most a 170°. An earlier opening stat won't prevent a problem cooling system but it will help in slowing down temperature rise momentum in Phoenix.

This can eliminate many potential overheating probs you might encounter. Once your car gets to the 195° temp in the Arizona sun, stop and go interstate traffic, with A/C on....... you're a goner. Your temp rise has too much momentum behind it.

With your A/C on and intense heat environment you really are holding your own at 240° considering the stock single fan setup doesn't come on til' 234°.

And... when I was in Phoenix for 10 years I had maybe 4 cars during that time and not a one of them would allow the use of the A/C.

The environment is just too intense for many cooling systems.

 

Run a compression check after you verify the temperature with a 2nd gauge. If you blew a head gasket and are pumping combustion in to the water jacket you won't ever keep it cool. I would say the next goodies you put on your car should be an HD aluminum radiator and at least dual low RPM fans. You need as much radiator as you can afford and as much air flow through it as you can get. This may not actually cure the cause of the problem, but its a good idea for your climate. It should give you enough cooling to once again run the A/C system without problems. Also, a good back flush will not unclog blocked tubes in your radiator. So you may need to pull the whole thing and let a radiator shop rod it and clean it out good. Last time I had this done the charge was minimal. That is when I discovered that the bottom 5 rows were blocked and the next 6-8 rows were mostly blocked. This was after back flushing and cleaning out the cooling system.

 

Grand Prix, my current radiator is less than a year old, so it souldn't be clogged, but I agree, when I can afford it, alum all the way!

Mike, I forgot about the fans not kickin in until way up there. I think I'll try riggin my thermo switch that runs my aux fan to run the main also, yet I need to find a dual fan set up. By the way, I've tried using a 180* thermo, but to no avail. Yet with the stock fan not working until 234* as you say, this would make sence.

Thanks again everyone.