Running Hotter After Maintenance Work?

**silverbird22** · 03-31-2008, 03:39 AM

Just finished up with my 100,000 mile maintenance work which consisted of:
New plugs and wires (stock A/C Delco)
Fuel injection system flush (dealer)
Fuel filter replace
All four O2 Sensors replaced (Bosch)
Replaced A.I.R. check valves (they were stuck closed and threw codes)
Transmission flush and fill
Now the car seems to run a bit warmer than before. (210-220ish) For example, when I get off the freeway the electric fans kick on after a couple of stoplights. Then when I park the car the low speed fans stay on for a minute or two. The temps here in Michigan are still quite cool (40's). Don't know whats going to happen when the hot summer temps arrive.
It doesn't get real hot. I just notice that the fans kick on more frequently than before this maintenance work was done.
No codes and the car seems to be running well.
Is this normal?
Any opinions on the situation?
Thanks,
Silverbird

**Too Fast** · 03-31-2008, 03:58 AM

I really don't think that kind of work did anything to make it run hotter. First thing I would check is the radiator, to make sure no bag or something on it blocking airflow. It is possible you are a little low on coolant, is it full? That does seem hot for cool spring days! Another possibility is a thermostat starting to stick, but I would first check the coolant level, in the radiator (after it cools off!) and also the overflow tank.

**silverbird22** · 03-31-2008, 05:38 AM

Originally Posted by Too Fast

I really don't think that kind of work did anything to make it run hotter. First thing I would check is the radiator, to make sure no bag or something on it blocking airflow. It is possible you are a little low on coolant, is it full? That does seem hot for cool spring days! Another possibility is a thermostat starting to stick, but I would first check the coolant level, in the radiator (after it cools off!) and also the overflow tank.

Overflow tank shows full. Should I do a visual by removing the radiator cap and looking in the radiator? Is it possible that the overflow tank shows full and the radiator is low? I do have a Fast Toys ram air set-up thats been on the car for the last 85,000 miles.(the sheet metal duct is sandwiched between the radiator and A/C condensor) Never had any heat issues before. Car has 118,000 miles now.
Thanks for the help.
Silverbird

**2001NBMZ28** · 03-31-2008, 09:26 AM

Yeah look inside the radiator with the car cool - is the low coolant sensor unplugged? Overheating can be caused by something as simple as the radiator cap not holding pressure anymore. The fans should shut off with the key, unless programmed to stay on for X minutes with tuning. The PCM will keep them running (stock) for a couple minutes key off if it sees an overheating condition - looked it up in my helms once but can't remember the trigger temp - thinking it was pretty high like 274? or something.

**silverbird22** · 03-31-2008, 09:42 AM

I unplugged the low coolant sensor a few months back. It would have been the fourth time it was replaced. It kept telling me it was low when it wasn't. I'll check the rad for coolant level tonight when it cools off. I did notice that the plastic overflow tank cap/dipstick seems to be stripped. It doesn't stay on real tight. Could this cause an air leak in the system that can cause high coolant temps?
Thanks for the help so far.
Silverbird

**2001NBMZ28** · 03-31-2008, 10:01 AM

Not sure about the overflow tank cap, but if it's been that way for a while probably not it. BTW looked up the trigger temp in my helms and it says 284 degrees will keep the fans on with key off for 3-4 minutes for an '01.

**silverbird22** · 03-31-2008, 10:16 AM

Went out and checked the coolant level in the radiator. Its right up to the top. (COLD)
I'm thinking thermostat.
I have a new 160 stat on my shelf but I think I'm going to buy and install a 180.
Don't think a 160 would be a good idea for year round use.
What do you guys think?
Thanks for the help so far.
Silverbird

**Too Fast** · 03-31-2008, 02:36 PM

Yes, I would try the thermostat first, since you've confirmed your coolant is full. the overflow tank cap, especially on our cars, won't cause any problems if it does not fit tight. I think they all feel like they are stripped, anyway. It is up to you what t-stat to use, I recommend the 180 unless you want to get every possible HP at the drag strip.

**SSTODD** · 04-01-2008, 11:25 AM

Seems way too hot for our cold weather now, my fans never run even in the summer. Nice to see another old fart from Michigan on here.

**jujofields** · 04-01-2008, 11:35 AM

Did you check to make sure the radiator cap is sealing properly?

**Orcus79** · 04-01-2008, 11:59 AM

100 000 miles on orginal t-stat and rad cap, replace em, its realtivly cheap insurance along with a coolant flush if one wasn't done recently.

**SVG210** · 04-02-2008, 05:14 PM

could be Air you your radiator system, Bad Cap, Thermo,

I doubt your T-stat is sticking due to that you still are on the 210-220ishes, but you can do a visual just start the car open the rad cap and check for yourself if the thermo opens, I personally dont like to remove the cap when checking the thermostat, I just feel the return line untill it gets hot.

**silverbird22** · 04-04-2008, 05:18 AM

Update.....
Had the coolant flushed and filled last November at the dealership.
Put a new rad cap yesterday. No change.
Temp gage shows normal, just touching (to the left) the 210 hash mark tab cruising down the freeway. Get off the freeway after a few miles, goes up to the right side of the zero on the "210" number on the gage. Fans kick in.
It shouldn't be doing this in 40-50 degree ambient temps.
I'm changing out the stat with a factory replacement this weekend.
Hopefully I have a sticking stat and this will solve the problem.
Thanks to all for the help.
Silverbird

"Seems way too hot for our cold weather now, my fans never run even in the summer. Nice to see another old fart from Michigan on here."

BTW SSTOD, if you've never had your fans turn on there may be a problem. You might want to get them checked. Can't really rely on these pos gages they put in our cars

**silverbird22** · 04-07-2008, 03:11 AM

FIXED!
Changed out the thermostat.
Temps are fine now.
Thanks for the help.
Silverbird

**SSTODD** · 04-07-2008, 03:17 AM

That's cool, in more ways than one! I meant that unless I am stuck in the dream cruise my fans never come on during normal use and never when it is 40 outside. Nice weekend huh?

**Too Fast** · 04-07-2008, 03:51 AM

I had my suspicions about that t-stat. Cool Driving now, eh!

**silverbird22** · 04-07-2008, 04:26 AM

Played around with the old stat when I pulled it out of the car.
It would intermittingly bind itself up on the spring.
Could have been the problem. (or just plain age)
Hopefully, winter is over!
Thanks again.
Silverbird