Recent Topics
What would you do in my situation?
by 55Test
12 minutes 31 seconds ago
fuel additives AS fuel?
by 55Test
17 minutes 3 seconds ago
Best Crimping Die for SA .223?
by 2015_PSD
26 minutes 3 seconds ago
Castrol Edge EP Viscosity Index
by Gene K
42 minutes 2 seconds ago
Iceland beats England
by hatt
Today at 03:51 PM
1991 Clean Acura NSX with some mods for $45k
by HTSS_TR
Today at 03:16 PM
Tiny metal particles suspended in oil?
by rustypigeon
Today at 02:35 PM
M1 0w20, 10,093 miles, 2006 Civic
by Patman
Today at 02:13 PM
5w-40 synthetic vs 15w-40 synthetic
by mbacfp
Today at 01:27 PM
SCAM!Anyone renting their water heater tank?
by KrisZ
Today at 01:16 PM
Donaldson PowerCore as HEPA filter?
by PeterPolyol
Today at 01:13 PM
Clearance oversized filters for M20x1.5 w/bypass
by PeterPolyol
Today at 01:05 PM
Newest Members
alostaunau, alanwayne1908, scuff, Tuar, ATFD48
58292 Registered Users
Who's Online
77 registered (alanwayne1908, 55Test, 007, 2009Edge, Alfred_B, 2015_PSD, 5 invisible), 1953 Guests and 10 Spiders online.
Key: Admin, Global Mod, Mod
Forum Stats
58292 Members
66 Forums
250891 Topics
4112247 Posts

Max Online: 2862 @ 07/07/14 03:10 PM
Donate to BITOG
Topic Options
#1253873 - 10/09/08 04:34 PM Code PO128- Thermostat??
exranger06 Offline


Registered: 01/25/08
Posts: 3286
Loc: Guilford, CT
My sister has a 2001 Saturn L200. The check engine light recently started coming on, so she takes it to Autozone and has them scan for codes. They came up with code PO128, "Engine coolant temp below thermostat temp."

I'm probably gonna replace the thermostat regardless, as I feel it's be a good maintenance thing to do. The only other thing I could possibly think of is maybe the coolant temp sensor. She said the fans were turning on even when it was really cold outside, which I think is probably normal, but it's also possible.

Anyone do a thermostat on one of these before? I know thermostats are generally very easy but I've never done one before, on any car. Any advice/insights/suggestions are very much appreciated.


Also, the thermostat located right where the upper radiator hose connects to the engine right? I know on most cars it is but this Saturn has some strange design elements from what I've seen so far.


Edited by exranger06 (10/09/08 04:43 PM)
_________________________
2006 Ford Ranger Sport
1992 Honda Accord EX
1994 Ford Bronco XLT (project)
2014 Subaru XV Crosstrek (wife's)

Top
#1253892 - 10/09/08 05:05 PM Re: Code PO128- Thermostat?? [Re: exranger06]
03cvpi Offline


Registered: 03/04/07
Posts: 175
Loc: Minneapolis
Fairly easy. Mouted on the front of the engine towards the pass side of the car. Don't loose the cardboard tube. The thermostat is pushed in and quarter turn to lock. If you have a mech mirror it's pretty easy to see. Most replacement t-stats come with the tube, if not a needle nose pliers will work, but on install be careful not to crush the t-stat.

Top
#1254329 - 10/10/08 09:46 AM Re: Code PO128- Thermostat?? [Re: 03cvpi]
eljefino Offline


Registered: 06/15/03
Posts: 29292
Loc: ME
^ That sounds right for a 1.9, is it the same for a 2.2 ecotec or 3 liter V6?

The fans will run when the car is cold if the AC is on, even as part of the defroster. If there's a CTS fault forcing the fans on there'll be a code for that too.

Diagnosing this much farther will probably take more time than the thermostat job. My experience with GM's is they usually fail cold, which is a good failsafe. \:\!

Top
#1254527 - 10/10/08 02:42 PM Re: Code PO128- Thermostat?? [Re: eljefino]
mechtech2 Offline


Registered: 09/05/06
Posts: 19479
Loc: Chicago Area
Make sure the mating surfaces are clean and corrosson free.
I am a fan of using a LIGHT coat of silicone RTV on gaskets and 'O' rings - no comebacks.
You may have a sensor problem. If the thermostat does not fix the problem, look there.

Top