coolant issues

[92rang]

hopefully someone can help me on this. all of a sudden the truck doesnt have heat. it seems to take a while to register temp but when it does it shoots up to normal real fast. it runs a little above the half way mark on the gauge. every now and then i get small blasts of heat from my heater but then right back to just luke warm. today i noticed coolant was bubbling out from what appeared to be one of the hoses right above the water pump. could this be a thermostat? it seems like it might not be opening when it should.

 

[rurouni20xx]

could be a thermostat could also be trash in the cooling system. when was the last time it was changed/flushed? its recommended to flush and fill every 2 yrs. your erratic temp gage makes it sound like a stuck thermostat, could either be bad or rust/trash blocking it making the truck run colder than normal. you need to address the leak as well asap. the thermostat is above the water pump where the upper radiator hose attaches to the upper intake plenum, two 1/2 or 9/16 bolts (cant remember which been a while since i did one) and make sure you get another gasket as well since that one will probably be dryrotted and flaky.

 

[jhammel85]

Is the coolant bubbling out of the hose where it meets with the housing?? Its a slight chance but...maybe theres a leak there and its letting air in...forming an air bubble in the system?

Since you don't have heat, I would 1st check your coolant level. If its low, you wont have much, if any, heat. Plus It'll idle high.

If thats good, Run it with the cap off and make sure it circulates and to get air out.

Check for leaks around the bottom of the water pump. Theres a weep hole that leaks antifreeze when the bearings have pretty much gone south. O

One more thing with the waterpump, would be to listen to the pump itself. I've done it in the past by rotating it by hand with the belt tension off of it. If it sounds kind like a scraping sound, its bad. One more thing would be to run the truck and take a hose and run it to the pump and to your ear...kind of like a stethoscope.

Wouldn't drive it until you are sure. Definitely don't want a blown Head Gasket!

Good luck man, Hope that helps.

 

[Big Jim M]

Your system is LOW on coolant! Park with the radiator up higher than the top of the dash and with the cap off and the heater on high run the engine and keep filling the radiator as the air comes out of the system.. Spend 20 minutes doing this.
Ok now you have it repaired and the heater should work fine..
NOW find the leak where you are losing coolant. Coolant is most likely slowly dripping out of a small leak somewhere.. If you don't find the leak you will surely burn a head gasket or crack a head very quickly now.
After finding and repairing the leak you must refill the radiator as above one more time.
Big JIm

 

[r1hatman]

My wife's van did the same thing, I replaced the thermostat and it worked fine after that.