Low cooling temperature

[amc74]

Hi everyone, newbie here!! I have a 2001 GP 3800 series, anyhow, I noticed today that my temp guage barely went over 100 degrees, NO check engine light came on. About a year ago, same problem, service light comes on, I scan it, change thermostat,(fail safe type) all is good. Facts to know: I NEVER flushed the coolant since I owned the car (7 years), I HAVE mixed green with red antifreeze in the past, ( I didnt know the difference back then). My theory is the stat could be stuck open from accumulated gunk floating around since it was never flushed. Any suggestions on this is GREATLY appreciated.

One more question, How exactly is the best way to open the radiator drain on the lower left side? I could barely reach it and if i remember, i tried needle nose pliers to crack it open and it wouldnt budge. I didnt want to break it.
THANKYOU!!!

I apologize for the long post!!

[BNaylor]

Welcome to AF.

100 degrees? Doesn't the low scale on the temp gauge start out at 160 degrees? The Dex-cool is only good for 5 years or 150K miles, whichever comes first so you are way overdue. Bad idea to mix green with orange Dex-cool so you need to flush the cooling system.

On draining the radiator go from underneath. Remove the plastic trim and use the tool shown in the tech procedure posted at our Tips & Maintenance. See link.

Click here

[Godofwarmike]

isnt there a problem with mixing the two that it causes them to clog up the rad?

[BNaylor]

Originally Posted by Godofwarmike

isnt there a problem with mixing the two that it causes them to clog up the rad?

What I do know for a fact is when the two coolants are mixed you will get sludge in the cooling system sooner or later.

[CrazyHorst]

It might be adviseable to undo the upper and lower rad hose and run a garden hose thru after the used coolant has been collected to confirm the radiator core is free-flowing.

[BNaylor]

I would exercise caution running a garden hose with unregulated pressure on a radiator direct. Reason is in most cases the city water supply pressure is too high. 50 psi plus. So make sure it is not turned up too high. Good way to blow the seals located on the plastic coolant reservoirs where the radiator core meets up.

[CrazyHorst]

50+ psi is entirely possible in the cooling system if you run WOT with a closed tstat, so not sure how to advise there. Granted the radiator is "protected" somewhat by the closed tstat although there is the bleed orifice to contend with but most is shunted somewhat by the flow control washer for the heater core.

Also...sealing up a garden hose to transfer full city-water pressure to either of the radiator hose(s) might mean a couple hours on the lathe turning up an adapter. Normally I have better things to do with my time and raw materials. My suggestion is to pour water in the top hose or port of the radiator and see what pours out the bottom.

[amc74]

Thankyou for your responses and yes, I made a mistake, the coolant guage starts at 160. Today it seemed to go up to 185 and I thought maybe the obstruction in the tstat (assuming there is one) had cleared itself, then it went doen to 165-170 which is not normal. Maybe the one year old thermostat is bad??

[tblake]

I myself would start with replacing the stat (since its a cheap part) and flush and fill the cooling system with the proper mixture of 50/50 or 60/40 Dex-cool with distiller water.

[amc74]

Thanks again everyone and also BNaylor for the tool tip. I will post my results after I take this on.

[bigstakz]

Hello guys,

I have the same problem if not similiar. I just got the code which came back as P0128 (2001 SE 3100). Can someone please tell me how can i fix this problem?

[BNaylor]

Originally Posted by bigstakz

Hello guys,

I have the same problem if not similiar. I just got the code which came back as P0128 (2001 SE 3100). Can someone please tell me how can i fix this problem?

The P0128 DTC is common if you live in a very cold climate area but if in a warmer weather area a problem. It means the PCM module has detected that engine warmup time via the ECT sensor is taking too long to properly warmup. Engine temperature rise too slow.

In most cases it is a defective thermostat but could also be a an ECT monitoring issue.

What does your temperature gauge at the IP read after sufficient engine warmup time?

[lil_nages22]

I guess I can post on here because I am having similar problems. I moved from Florida about 2 months ago, and never had a problem until moving back to Indiana. The running temperature of my car ('00 GTP) is barely above 160, even after long periods of driving. It used to warm up right to the first line (185 I believe, and hopefully this is normal). There is a code set but have not retrieved it yet. Also I have noticed a decrease in fuel mileage but this could be due to winter gas (if I reset on highway, I get about 25 mpg, when i used to get near 29). I'll take any ideas you guys have for me. Thanks.

[BNaylor]

Originally Posted by lil_nages22

I guess I can post on here because I am having similar problems. I moved from Florida about 2 months ago, and never had a problem until moving back to Indiana. The running temperature of my car ('00 GTP) is barely above 160, even after long periods of driving. It used to warm up right to the first line (185 I believe, and hopefully this is normal). There is a code set but have not retrieved it yet. Also I have noticed a decrease in fuel mileage but this could be due to winter gas (if I reset on highway, I get about 25 mpg, when i used to get near 29). I'll take any ideas you guys have for me. Thanks.

It would help to post the code (DTC) so we don't speculate. A thermostat opening too soon or staying open (stuck) could cause your symptoms or reduce fuel economy due to longer engine warmup times. Are you using premium unleaded gas?

[lil_nages22]

Originally Posted by BNaylor

Are you using premium unleaded gas?

I sure do, every fill up.

And I will try to retrieve the codes soon. Moving across state this weekend, so it will be next week sometime.