Radiator fans in colder weather

JT4SC · October 31, 2012, 07:08:34 AM

Hey guys,

I'm excited to be taking a group of friends in the Moose this Saturday for some tailgating and USC football. We have to leave San Diego at 5am to get to LA in time to guarantee a RV spot. It will be cold (relatively) - somewhere around 50 or so for most of the trip up north. Last time I did this trip the engine temp stayed below normal, which I am not sure is a good thing or not? My question is should I leave the radiator fans on (there is a manual switch by the fans) or turn them off so the bus can get up to normal operating temperature??

I have a 1993 MCI 102C3 with 6v92 DDEC.

Thanks guys!!

Jimmy

lostagain · October 31, 2012, 07:27:46 AM

The thermostats should take care of engine temperature. Maybe they are stuck?

JC

TomC · October 31, 2012, 07:50:20 AM

When I was driving my 1980 KW with 8V-92TA, I never had a winter front on the truck. The engine would come up to at least 175 even in sub freezing weather. If your engine doesn't get up that high, you need new thermostats. Good Luck, TomC

JT4SC · October 31, 2012, 08:02:20 AM

Quote from: lostagain on October 31, 2012, 07:27:46 AM
The thermostats should take care of engine temperature. Maybe they are stuck?

JC

Thanks for such quick replies!! The temperature gauges are working (meaning they go up and down), but maybe they need an adjustment? Is that something I can do myself or will it require a mechanic?

lostagain · October 31, 2012, 08:08:31 AM

There usually is a mechanical temperature gauge in the engine compartment. Compare your dash gauge with that. You could also use an infra-red hand held thermometer aimed at the thermostat housings. You probably need new thermostats. Not a big deal to replace.

JC

luvrbus · October 31, 2012, 08:15:47 AM

Could be just the seals sometime T stats are changed and they are not the problem

good luck

JT4SC · October 31, 2012, 08:19:04 AM

Quote from: luvrbus on October 31, 2012, 08:15:47 AM
Could be just the seals sometime T stats are changed and they are not the problem

good luck

Awesome, thanks guys!!!

sledhead · October 31, 2012, 03:05:43 PM

After I replaced my thermostats in the fall my temp. went up to 175-180 and stayed there .1st time in 2 years after full rebuild . tested the 2 year old t stats , they worked fine on the stove ? can't explain it .The cost of new t stats,gaskets were $120.00 tax,del incl. 6v92ta 1990 dave

John316 · October 31, 2012, 07:36:14 PM

Quote from: JT4SC on October 31, 2012, 08:02:20 AM
Thanks for such quick replies!! The temperature gauges are working (meaning they go up and down), but maybe they need an adjustment? Is that something I can do myself or will it require a mechanic?

Whoa....Hold on a second. We (they) are not talking about your temperature gauge.

Let's see if this works. Your engine is supposed to be kept at a pre-determined temp while running (after warm up, of course), usually about 185. The thermostat's that they are talking about are in the "engine" area. When the coolant is getting too hot, they open and tell the radiator fans to turn on. When the bus is warming up, the t-stats are closed (or almost) cutting the radiator out of the loop, causing the engine to circulate it's own heat back through again. When it reaches that perfect temp, the t-stat opens again to let the radiator cool the coolant down. Of course, that is a way over simplified explanation, and the tstats should not always be open or closed.

With that in mind, in your situation, your bus may not be able to get up to temp because coolant is always in the "cooling off" mode going through the radiator. That could mean that the t-stat has gotten stuck in the open position making your engine run to cool.

Make sense?

FWIW

John

JT4SC · November 02, 2012, 12:26:11 PM

Yes it does, thanks John!! My next question (and probably an opportunity for everyone to laugh at me) is can I tap on a part of the engine where the t-stats are housed that may help free them up?

Hi yo silver · November 02, 2012, 01:35:43 PM

Does Jimmy's 102 not have thermostatically controlled radiator shutters like my MC9? If so, I would suspect the shutters might be open all the time.
Dennis

JT4SC · November 02, 2012, 03:31:42 PM

Hi Ho Silver,

All I know about my radiator fans is they have a switch I can turn on or off at the rear of the bus. What I believe I remember was sometimes the radiator fans wouldn't kick on right away, they usually kicked on later. Now it seems as though they kick on right when the bus starts. I assume that also has to do with the t-stats or is there a separate "shutter" I should know about?

Hi yo silver · November 02, 2012, 05:41:19 PM

I'm not sure if your radiator configuration is like mine. I can see my shutters through the screens on the rear corners of the bus. They look similar to venician (sic) blinds. They stay closed until the specified temperature (175?), then open and close automatically as needed. I'm sure someone more knowledgeable will chime in to help. Good luck.
Dennis