Chooch

Just finished my headgasket job on my 95 4Runner with the 3.0

Cooling system isnt building pressure but the temp gauge is nice and low where it should be. Not really getting heat out of the vents though. What are your guys opinions? All I can think of is theres a leak somewhere, but im definitely not leaking coolant. How can I check this without a pressure tester? Or is that the only way? Thanks

Marc

I believe the cooling system "builds pressure" by the expansion of the heated fluid.
It's not really pressured like a garden hose. The water pump is for circulating the fluid not building pressure.

Your best bet is to rent a pressure tester to see if it "holds" pressure.

snobdds

I bet you have an air pocket in the system...So burp your system.

Lots of good threads on how to do it...just search a bit.

Chooch

Tried burping it, no luck. Just ran it on my driveway which is a pretty steep incline for about 20mins with the cap off. Still nothing, my biggest concern is I don't have heat.

Anyone have any ideas?

rworegon

Are you sure the heater valve is open and letting coolant into the heater core? Have you had the rig out on the road for a spin to see if you get heat with a higher engine load?

I know on my rig, idling in the driveway takes foreever for the heat to warm up if it is cold out.

Chooch

How do I test the heater valve? Just did the headgaskets might have screwed that up

rworegon

You should be able to someone else move the heat selector from cold to hot and see the valve control move under the hood. Seems there is another test method, but it escapes me right now.

Sure you have all the coolant hoses routed correctly?

Chooch

Pretty damn sure I got them all routed right. Unless I crossed one with an air hose on the passenger side of the plenum...

Know where I could get a diagram of that stuff?

rworegon

Use the Change Vehicle to put in your rigs specs. There are diagrams that you can pull up.

http://www.toyomotorparts.com/sectio...rts-11946.html

Turd Furgeson

Your thermostat could be stuck open too. My camaro did that once. Would not build pressure one day after driving all over town,temp gauge would not move off the bottom (aftermarket gauge starts at 130*) and ran like crap from not getting warm enough. Pulled thermostat out and it was stuck open. Put a new one in and problem solved. That was something that happened to me that one time anyway. Doesn't automatically mean that's your problem, but might want to look in to that.

Chooch

Side of the plenum I was concerned about doesnt even have any water inlets.

Thermostat is definitely not stuck open, even if it was I would still be getting heat wouldnt I?

rworegon

Yes, you'll get some heat when its stuck open, but less than you should and it will take longer to heat up and it takes more work to maintain heat. Do you have a Toyota OE 180 deg t-stat in there? And, was it replaced when you did the HG?

Chooch

Pretty sure its the original.

Boiled it in water and it opened, so I assume its still good. Didn't have a problem with it before.

It also doesnt take very long for the engine to heat up

rworegon

T-stat sounds ok......

Coolant valve not opening, routing issue, or a blockage in a hose feeding the heater are all that comes to mind. Hope others chime in.