GIVE ME HEAT

[Jamie]

No heat on these cold Canadian nights. Might get up to 190 on the gauge but soon as the thermostat opens 150. It'll do this maybe 20 times in a 60 mile trip. Thinking i got a dud t-stat

[sinkrun]

Take both heater hoses off at the firewall then run water from a garden hose in and out both brass connectors for several miniutes you should see gobs of brown come out. What your doing is flushing the heater core. Worked like a charm on mine.

[Jamie]

Already flushed. No change. No heater control valve don't need that in the winter(Do I). Y's were replaced with T's that might have been a mistake.

[jpnjim]

Big rigs cover part of their radiators in cold weather,

so the radiator doesn't overcool the engine.

 

I never had an XJ/MJ that needed that,

but it sounds like you are overcooling.

 

You could try some cardboard in front of one side of your radiator.

I'd cover some of the drivers side and see what happens.

[JeffN]

Change the thermostat, if you are under 190 on your temp gauge then it is opening way too early or stuck open

[Geonovast]

I would verify your gauge is correct before doing something else.

 

Could be air in the system. Try burping it.

[ParadiseMJ]

Change the thermostat, if you are under 190 on your temp gauge then it is opening way too early or stuck open

 

Can't hurt replacing the t-stat (195*F).

[jpnjim]

If the temp goes to 190, then drops, the thermostat is cycling.

 

When the thermo opens @190, the cold water in the radiator rushes in, drops the engine temp.

Then thermostat closes, and it starts again.

 

Sounds like the thermostat is working.

 

 

I'd say either:

 

1) It's too cold out, and your radiator is overcooling your engine

 

or

 

2) Your coolant level is low (= no heat), AND your gauge is incorrect (possibly due to low coolant levels).

 

#1 seems more likely to me. :dunno:

[Jamie]

Everything flushed, T-stat replaced. All working good. two hot heater hoses. Running around 160. Good heat as i switch from vent to heat but then it's cool again. I can feel some heat under the dash. ??????????????????

[ParadiseMJ]

Hey, check the cable above your passengers left foot. Move the Hot/Cold lever on the dash...does it move, or is it even attached??

 

OR...take out your radio and see if the vacuum "junction" behind it is intact and not leaky.

 

OR...make sure your vacuum lines to the vac reservoir and the resrvoir itself are in good shape. Replace any questionable lines. Vacuum line is cheap. I always recommend my own version of a vacuum smoke test. Cigar...blow a puff or two into the main HVAC vac line. Watch the smoke, find your leak.

[Jamie]

Checked the cable it works well. Now to check for vacuum leaks.