'05 Grand Prix is getting hot w/3.8L

[Merkava_4]

Originally Posted By: volk06
The coolant level is good and both fans are kicking on and running.


But what is the condition of the coolant? When's the last time it's been changed? The 3800 in my Buick runs very
cool all the time. On a 100F day with the AC on, and both fans on, it'll run 185F. Turn the AC off on the same
100F day after the AC has been on and the water temp will shoot up to 200F with the car stopped and the engine
just idling. Get the car moving again and the water temp will drop down to 191F. Turn the AC back on and the
water temp will drop back down to 185F. On a California Winter day while driving on the freeway and with the
radiator catching lots of air, it'll drop down to 170F no problem.

These engines run very cool as long as the cooling system is functioning like it should and you have fresh coolant.
Going by what you've described, and in comparison to my 3800, I'd say you've definitely got something wrong with
your cooling system.

 

[Drew99GT]

If yours is running at 185, then your thermostat is sticking cold or is weak on the cold side. The thermostat is 195 degrees.

 

[Merkava_4]

Originally Posted By: Drew99GT
If yours is running at 185, then your thermostat is sticking cold or is weak on the cold side. The thermostat is 195 degrees.


The cooling system in my Buick is operating very nicely; I can assure you of that.

 

[Drew99GT]

The stock thermostat is 195; did you install an aftermarket one?

 

[Merkava_4]

Originally Posted By: Drew99GT
The stock thermostat is 195; did you install an aftermarket one?


No sir, it's an ACDelco from the dealer.

 

[onion]

Any signs of Dex-Sludge? What about leakage at the intake? Both are common with the 3800 of this vintage.

 

[volk06]

Coolant was fresh 15,000 miles ago. I think I've found the problem, there is at times a loud whining noise that comes from the engine, from what I found out is a common sign of a bad water pump.

 

[SteveSRT8]

Hard to believe with only 71k miles. For a 3800 that is NOTHING.

But anything is possible.

 

[volk06]

Yes I was kinda surprised to be having this problem. Next weekend I'm planning on replacing the water pump and thermostat, both will NAPA parts. Since I'm doing this I'll be changing out the antifreeze - any thoughts on what kind i should replace it with?

 

[Drew99GT]

If you want to get rid of the Dexcool, use Peak Global Lifetime.

 

[volk06]

is there any pro/cons of dexcool?

 

[Drew99GT]

Originally Posted By: volk06
is there any pro/cons of dexcool?


There's been a fairly well documented history, to include a settled class action lawsuit against GM's use of Dexcool, that Dexcool causes problems such as sludging, weakening gaskets, clogging heater cores and radiators etc. In my experience and many others, if you maintain the cooling system religiously, you won't have problems with Dex. One thing of note is, the problems, at least sludging and Dexcool turning to mud, happen when it becomes exposed to air for long periods, such as when there are leaks in the cooling system and the level starts dropping in the radiator and it's not topped off.

IMO, if you change it more often, say every 50,000 miles instead 150,000 miles, make sure there are no leaks and keep the system topped off, and ONLY use distilled water in the mixture, you'll likely have a spotless cooling system. My Dad's 1999 Olds 88 with 195,000 miles has everything original in the cooling system, and it's had nothing but Dexcool and it's crystal clean.

 

[mechanicx]

Originally Posted By: volk06
Coolant was fresh 15,000 miles ago. I think I've found the problem, there is at times a loud whining noise that comes from the engine, from what I found out is a common sign of a bad water pump.


I doubt your problem is the waterpump. More likely the whining is coming from a belt tensioner or idler. Even if the waterpump was whining which isn't very common i doubt it is the cause of the engine running hot. I would just change the T-stat. It is the most likely culprite and easy to change on this engine. My 3800 runs cool even on a hot day idling in traffic.

 

[Merkava_4]

Originally Posted By: volk06
is there any pro/cons of dexcool?


I've had no problems with it. I change it out once a year along with distilled water.

 

[Drew99GT]

http://www.ls1tech.com/forums/general-ma...obably-why.html

Trying to figure out why my Dad's Olds is running a bit on the hot side, especially with the A/C on in slow traffic, I found that thread. I just went and took the rad support off to look in between the radiator and condenser and HOLY MOTHER OF GOD. The radiator is filled with leaves, pebbles, and various debris. Perhaps that's the issue Volk. Given your location of Iowa, I'd imagine your radiator and condenser are covered with dead bugs.

I'm gonna take the car in and have them take the rad and condenser out and clean them.

 

[The_Eric]

Someone had mentioned to check for air flow restrictions in the radiator; I think this is also a great idea...


Originally Posted By: volk06
Coolant was fresh 15,000 miles ago. I think I've found the problem, there is at times a loud whining noise that comes from the engine, from what I found out is a common sign of a bad water pump.


In my experience, water pumps don't generally whine. If they make any noise, it's usually a light grinding noise; like that of a failing bearing.



Originally Posted By: volk06
Yes I was kinda surprised to be having this problem. Next weekend I'm planning on replacing the water pump and thermostat, both will NAPA parts. Since I'm doing this I'll be changing out the antifreeze - any thoughts on what kind i should replace it with?


Do yourself a favor and use an O.E.M. stat. They do work differently. I've found out on too many occasions that the aftermarket pieces are sluggish to temp and in one application, wouldn't get to temp at all on a cold day.


Originally Posted By: volk06
is there any pro/cons of dexcool?


It depends on who you ask. The pundits of Dex Cool are always quick to point out problems, but generally speaking those with problems are those who pay no attention to their vehicles until their mechanic says that their radiator is sludged up. The key to Dex systems is maintenance. Replace your pressure cap periodically and keep the coolant level overfull (in the overflow tank) to keep a little extra head pressure on the line going to/from the radiator to help the radiator cap function- it's actually GM recommended.

Naturally there are those who will have problems with Dex, or anything for that matter in spite of taking supreme care of their car... It happens. But the majority of those who stay on top of their maintenance wont.

If you want to use a different coolant, feel free. Just know that the typical Prestone "All Makes" coolant contains some of the same inhibitors as Dex Cool, so if you're trying to stay away, consider yourself informed. Peak makes a good coolant in their "Global Lifetime" if that's the route you're leaning towards. Other alternatives are the traditional "Green", but be aware that you'll have to change it more frequently and GO5.

Now, all of these coolants are good, but none will protect you from the dreaded lower intake manifold gasket failure. It's not just limited to systems filled with Dex. I know - I've replaced lots of them...

I hope this helps!

 

[volk06]

I already had a NAPA thermostat so I went ahead and installed that to see if that was the problem. If the problem is fixed I'll replace it with OEM one. It was only $7 so if it fixed the problem I wont be out much plus it only takes 5 minutes to replace.

 

[951Indy]

My 03 Bville exhibited the same symptoms. Temp would creep up in traffic, both fans on. I lifted the rubber cover above the rad and found lots of clogging from road debris. 3 minutes at the car wash with the wand (shooting from above the rad) and it stays pegged at 200, regardless of ambient temp, traffic, AC on, etc.

It has the original rad at 232K miles, but I changed the pump at 195K. Prestone since 75K miles.

 

[Drew99GT]

I just cleaned out the radiator and condenser on my Pop's Olds 88. Was a bit of a PITA; removed the fans and used the exhaust on my shop vac to reverse blow the dirt, pebbles, and debris out from the radiator fins and condenser fins. It probably had 2 cups worth of sand stuck in it and a bunch of those fluffy seed pods covering the front.

Afterwards, I let it idle with the A/C on full blast and it didn't get above at 205 degrees (has a Stant 195 degree superstat), and the A/C is blowing colder as well.

Volk, I'd seriously consider doing that. Your problem seems like a low airflow problem. If you have a really strong shop vac where you can hook the tube to the exhaust to blow air, it should fix the problem.

 

[volk06]

I replaced the thermostat and took the plastic off and rinsed out the radiator yesterday. Today it still got hot. Next step will be buying a new rad cap and seeing if that will make a difference.