TimRATH

I just purchased a '96 T100 and the temperature gauge gets to temp quickly but the heater never blows out really warm air. Does anyone have an idea of where I could start to look for the problem?

FalseAllure

Thermostat, Heater core flush and a coolant flush is what i would do first. I had the same problem on my 93 pickup.

TimRATH

How hard is it to flush the core and coolant flush? Is it easy to access the hoses going into the core?

ET

my 95 4runner just had the same issue. fill up your radiator and then drive it out on the highway for a few minutes and park it somewhere for a few hours to see if you're leaking antifreeze somewhere. my water pump was shot.

jrohland

Since your temp gauge is showing good temp I would not expect it to be a bad thermostat, water pump or low coolant.

It is most likely a plugged core but it could be a broken heater valve control cable. Look on the firewall under the hood near the top about in the middle you should see the valve. Move the temp control from side to side and see if the valve position changes.

If the valve moves you are most likely looking at a plugged core. You can try to flush it but it is not easy.

WARNING! Removing the hoses from the core can be really hard. There is a good chance you will damage the core pipes and/or hoses trying to remove them.

If you can remove the hoses flush the core with a water hose. Try to blow out the water with a shop vac. Plug the low side with a cork or stopper and fill it with radiator flush. Let the flush sit for a day. If it is cold put a heater inside the cab to try and keep the interior warm so the flush does not freeze (plus it works better warm). WARNING!! Don't set your T100 on fire with the heater.

The flush MIGHT loosen the sludge which you can flush out with the water hose.

Good luck and be prepared to replace the heater core and hoses which you will likely have to do to fix this.

TimRATH

Thanks for all the advice...I changed the coolant and flushed the core. It seemed to help a little but not much. Where is the thermostat located? I will try and replace that today.

BamZipPow

4 or 6 cylinder?

Either way...just follow the bottom radiator hose to the engine block. It should be located there.

TimRATH

Is that pretty easy to replace and will I need to drain the radiator to do it? It is a 6 cylinder

BamZipPow

It will be easier to just drain the radiator and not have to worry about the antifreeze gitting all over the place. Just git a 5 gallon bucket to drain it into. If it's still good, you can re-use it again...

The 5vzfe engine is rather easy to replace the thermostat. Just make sure you git the stock thermostat with the jiggle valve and a new rubber gasket.

I still say you need to disconnect the heater hoses and flush the heater core really good.

YellowTT

hi,
1st sqeeze at radiator hoses while the vehicle is cold and not running with the cap off. if you have enough coolant start your vehicle and let it run with the cap off (if your coolant is low add coolant). Start your truck and wait a few minutes until it is at normal operating temp. at this point set your the blower to hot and turn the blower while vehicle is running with the cap off. Rev engine a little if needed to bring heater core hoses up to temp. At this point both heater core hoses should be hot and at almost the same temp. Your top radiator hose should be hot and the lower hose should still be cool but heat should be felt inside the vehicle. At this point set the blower to cold with cap off until your T-stat opens this will take a few minutes (hint both radiator hoses should be at the same temp and you should see the coolant flowing inside the radiator). Now you can install the radiator cap and any air in the cooling system is now purged. If you still do not have heat blowing or there is a major difference in temp between the heater core hoses let me know to move to the next step.
Good Luck