M1009 Running Cold

[pinbill]

Hello All-

Just finished installing plumping for two tank WVO system and now the truck is running cold, before the adding the extra 15 ft of 3/4 coolant hose it would run 170 consistently, now i am lucky to get 155 at idle and 140 on the highway. Changed the thermostat to an 180 on from LMC. Thinking about adding a grille cover, any other ideas would be greatly appreciated.

Bill

 

[four_by_ken]

Whats the air temperature?

 

[Westech]

LMC? you know the local auto parts store should have them for 1/2 the cost right?

 

[pinbill]

thanks for the reply,

air temp was 60F today, paid 3.95 at LMC couldn't find one locally for 1.975

 

[four_by_ken]

thanks for the reply,

air temp was 60F today, paid 3.95 at LMC.

You should be able to warm up a those temps. Even with the extra hose.

Strange.

 

[dmc-4359]

How do you have it plumbed? If you have routed your coolant like the heater core system, your thermostat would never enter into the equation. Even one gallon of oil is a fair amount of thermal mass to compete with, how many is your system trying to heat?

 

[pinbill]

I do have the plumbing tapped into the lines that go to the heater core. One tee going into the coolant line that goes from the thermostat housing to the heater core and the other tee going into the line that goes from the firewall to the radiator. There is quite a bit of extra coolant line in the truck maybe 16ft of 3/4 line and 12 ft of 3/8 coolant line. Is that really enough to by pass the thermostat? How else could I plumb the lines?

Thanks for your help,

Bill

 

[dmc-4359]

No problem.

Your plumbing decision bypassed the thermostat, not the extra volume of coolant. The volume of coolant is simply removing enough heat from your engine that it reaches equilibrium at 150 degrees instead of a temperature above 180 as it should. I don't know what your tank capacity is, but anything over 10 gallons will also be a significant thermal mass to overcome from a diesel engine with no load. When you're driving, that loads the engine but that also moves a lot of air past your lines and they will conduct heat away without any hassle. Insulating your lines will help you on the street.

Why the 3/4" line? From what I understand, most people use a 3/8 copper setup for routing coolant for this type of application.

 

[Warthog]

Hello All-

Just finished installing plumping for two tank WVO system and now the truck is running cold, before the adding the extra 15 ft of 3/4 coolant hose it would run 170 consistently, now i am lucky to get 155 at idle and 140 on the highway. Changed the thermostat to an 180 on from LMC. Thinking about adding a grille cover, any other ideas would be greatly appreciated.

Bill

From the Tpub.com webpage the thermostat has the following requirements:
BELLOWS
TO CONTROL ENGINE COOLANT TEMP
FLANGE
175.0 DEG FAHRENHEIT MINIMUM AN

It appears that you are not using the "hockey puck" thermostat if you only paid $4 for it.

I have been told that the cheap thermostats don't work properly with the CUCV engines.

The factory thermostat is GM 14077122.
Napa has a 190 degree and Murray makes a 195 degree.

Here is some thermostat info I post just last night, as I have working on system now.

Thermostat Info

The Hockey Puck thermostat for the CUCVS are available at NAPA, Autozone
and Oreilly's (and others of course).

NAPA - 381190
Autozone and Oreilly's - Murray 42995

Thermostat housing gasket - Felpro 35271, Murray 2140

Thermostat Housing (Water Outlet) - Murray 84987

With the extra plumbing I would put a hotter thermostat in.

 

[pinbill]

Put the new napa 381190 in today and still the same results. I have a digital thermometer at work that I will bring home tomorrow to check the temp on the surface.

 

[reallybigboat]

I've had the exact same problem with my M1009 after installing a new aluminum heater core, due to original copper core leaking. Totally stock set-up. I've done everything, including new NAPA hockey puck thermostat, made certain the diverter doors in the heater box are closing all the way (checked multiple times with cable removed), measured temps all over the place with my digital infrared thermometer, etc. No luck. Heater discharge is about 88-90 F on a 50-60 F day. Thermostat housing on engine is about 150 (with new hocky puck 190 F NAPA thermostat), heater inlet and outlet hoses at firewall are somewhere in the 136/130 F range.

The only thing I can think of is that there might be some air leaking in and around the heater core box, sucking cool as opposed to air through the heater core. I'm about to pull the entire box and heater core again to check how it seals. I also removed some of the factory very thin insullation on the inside of the diverter doors when I cleaned-out the heater box, but I don't imagine that makes much of a difference.

I have read other CUCV owners have similar problems with the heat or lack thereof. There seems to be no reason behind some trucks with good heater temps and some with marginal heat.

Best of luck!

 

[pinbill]

Thanks, I went out today and checked the thermostat housing with a digital thermometer and got 133 and the temp gauge was right on. At least I don't have to mess with gauge. This weekend I am going to mess with the plumbing a bit. Would putting a valve on the line that goes from the thermostat housing to the heater core help. This way I could shut off the loop to the heater core and my WVO system to heat up and turn it on when I switch over. Would a valve there mess anything up, like creating too much pressure from the water pump?

 

[dmc-4359]

No, the coolant system doesn't work that way. In fact, blocking up the flow of coolant is exactly how the thermostat works to regulate the engine's temperature. The only significant pressure that gets created in a cooling system on a normal automobile engine is from heat.

 

[Warthog]

I have been trying to figure this out in my mind (I know a scary thing). Post #8 hit it on the head.

With the plumbing you have, you have basically bypassed the thermostat and radiator. By adding the new tanks and tapping into the heater lines, you have created a new "radiator" that doesn't have a thermostat.

When the engine is cold and the thermostat closed, a limited amount coolant passes thru the crossover tube, out the heater nipple, thru the heater core and back to the radiator.

The coolant doesn't cool off enough to surpass the heat generated by the engine. As the engine heats up, the thermostat finally opens.

Now the coolant flows all the way to the WVO tanks and cools off, so the engine never has the chance to heatup and the thermostat to open. It also causes the heater core not to get as hot.

To test this, purchase a couple of rubber caps and "temporally" disconnect the WVO tank and see what happens.

 

[dmc-4359]

I agree and am a big fan of the pictures. Capping off the WVO system will likely address the operating temperature issues but even if the WVO setup is later plumbed to work inline with the radiator, the engine will not make enough heat to warm the WVO tank. As it is, the WVO tank by itself is enough to remove too much heat from the engine. That may change when ambient temps are 90+ but at 60 it is too much of a heat sink.

Have you considered using a separate closed loop system that draws its heat from the exhaust system? Basically wrapping a copper tube around the exhaust tubing as close to the engine as you can. Not sure how much conductive surface contact you'd need, I'm pretty sure it would require a small DC powered water pump to circulate though. Once you get the contact surface right to get your "coolant" to ~160 degrees, you really wouldn't need any kind of thermostat or anything for further temperature regulation.

 

[pinbill]

This weekend I will change the plumbing putting the valve right after the crossover tube from the thermostat housing so I can shut of the WVO system and the heater core and let you know how it works. Will this hurt the coolant system, water pump, or radiator?

Bill

 

[pinbill]

Well, I put in a valve right after crossover pipe to block of the heater core and the WVO system, put a grille cover on, and tested the temps with digital thermometer; still only 150 at best with heater core and system blocked off. With high RPM the temps are lower, I am running the NAPA 381190 thermostat, should I try the thermostat from the gm dealer is that any different? Maybe I will try putting it in backwards and if it overheats that will let us know if it is sticking open or not!

 

[pinbill]

Just to follow up, turned the thermostat around and the thermostat housing got to 170. I am thinking I will have good luck if I find a good thermostat. Calling GM tomorrow to get an OEM one.

 

[Zero_cool]

Just to follow up, turned the thermostat around and the thermostat housing got to 170. I am thinking I will have good luck if I find a good thermostat. Calling GM tomorrow to get an OEM one.

Anyluck with your heater? I to am having problems heating up my cab i ordered the 381-190 thermostat, it will be here tomorrow.

 

[pinbill]

The motor ended up heating up OK, it turns out I had the temp sensor in a bad spot in the rear of the motor screwed into the block out plate and it wasn't getting accurate readings. I changed it to the drivers side spot in the block and it gets up to 195 pretty well. Good luck with your truck sorry I can't help more.