Code 0128 Engine too cold.

[CEHollier]

My car has been Lund flex tuned/JLT/Reisch 170 for over a year. Running E85 presently. Check engine light came on. Went to Auto Zone and got Code 0128 - Coolant temp below thermostat regulating temperature. At highway speeds 55-75 mph head temps ranged from 158 degrees F to 180 but mostly below 170. Ambient temp is 55 degrees F. Anyone have this with a Reisch thermostat? Considering going back to 180 thermostat.

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[foghat]

I have the reisch 170

At idle (for a number of minutes), I usually see see cylinder head temps of about 194-198F once fully warmed up - including today where ambient temp was about 14f.

While driving at highway speeds, usually see head temps of about 186-190ish, again, including today.

I'm certainly no expert and am not sure what your issue is - but not sure it is the thermostat - if it wasn't working correctly and it failed open at 170 (or at all), you would be seeing really high temps. If it opened too early (before 170) - wouldn't that just make it take longer to get up to proper operating temp? I would think you should still get there eventually. But again, I'm no expert.

 

[Chameleon]

Warm it up.

 

[Xavier]

I also have a Lund tune and had the Reische t-stat. It started doing the same thing after a few months. Started gradually and then eventually the engine just wouldn't reach operating temperature no matter how long I drove it. It would run a little rough and I got two codes, one like the one you got and another for a thermostat problem. I had to put the stock one back in. I think it must've gotten stuck in the open position.

 

[EcoSwag1990]

Yea it sounds like it might be stuck open. Those temps seem way too low

 

[Gibbo205]

Low temp stats are a bad idea.
Good way to thin your oil due to fuel dilution.....

Thats bad for your engine!

 

[CEHollier]

Thanks guys. Has anyone changed the thermostat without draining the system? An idea I had was remove bolts from coolant tank and tilt it on its side so it won't drain out. Then open the thermostat housing and replace the stat. Then replace what ever coolant was lost I already have a gallon of Ford 50/50 mix. I may have to hose out any spillage but it seem like my idea would work. What say you guys?

 

[foghat]

you don't have to drain the 'system' so to speak. There is a drain plug on the bottom passenger's side of the rad you can use to drain that. Then you can pull the stat with no loss of fluid.

I seem to remember reading you don't actually lose too much coolant if you just pull the stat without draining first (just makes a bit of a mess, obviously) - but can't remember for sure if my memory is accurate....

 

[foghat]

If you do change back to a 180, I'd get in touch with Lund and see if will set the fans to turn on back at the default settings. Otherwise they are going to be running on high an awful lot.

 

[tom_sprecher]

Low temp stats are a bad idea.
Good way to thin your oil due to fuel dilution.....

Thats bad for your engine!

Someone designed this engine to be run at the OEM stat temp. Remind me again what is to be gained by using a 170 stat?

 

[CEHollier]

Someone designed this engine to be run at the OEM stat temp. Remind me again what is to be gained by using a 170 stat?

Fans run less.

 

[Gibbo205]

Someone designed this engine to be run at the OEM stat temp. Remind me again what is to be gained by using a 170 stat?

As I said they are a bad idea. Engines are supposed to run hot within designed specification, helps burn of fuel preventing oil dilution.

 

[CEHollier]

As I said they are a bad idea. Engines are supposed to run hot within designed specification, helps burn of fuel preventing oil dilution.

I have gone back to the factory stat. All should be good.

 

[Sasuketr]

I have the same setup. Thats one reason i wouldn't run E85 in winter conditions, especially in midwest. The car runs significantly cooler with 93 octane ranging from 180 to 185 in winter, 190 to 195 in summer. Going below 170 seems not normal but maybe possible with E85.

 

[Sasuketr]

My car has been Lund flex tuned/JLT/Reisch 170 for over a year. Running E85 presently. Check engine light came on. Went to Auto Zone and got Code 0128 - Coolant temp below thermostat regulating temperature. At highway speeds 55-75 mph head temps ranged from 158 degrees F to 180 but mostly below 170. Ambient temp is 55 degrees F. Anyone have this with a Reisch thermostat? Considering going back to 180 thermostat.

Do you happen to have an open grill also?

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