heater core?? (1 Viewer)

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How can you tell when your heater core is bad? My heater is blowing cold air 1/2 the time. The temp gage is jumping up and down but never gets out of the range it should be in. I am confused.
 
If this is about a FJ60, wrong forum, but I'll see if I can help you out.

It sounds like your's might be corroded or clogged, slowing the flow (the warm temps and cold air) and then pressure builds and clears the clog (lower temps and warmer air). I would try flushing the whole system and if it isn't too much of a hassle (never looked at a 60's heater-core), take it out and see if it is corroded or clogged.

Check your hoses, lines, radiator, anything that might have corroded or gotten clogged, also might wanna check for coolant in your oil (incase there is a leak in the head).

If this doesn't work, I'm not sure what to tell you...the heater core on our old Explorer had gotten clogged from using tap water (well water, before a water softener) and was giving the same problems, a flush and 50/50 coolant and distilled water solved it.
 
preacherman said:
How can you tell when your heater core is bad? My heater is blowing cold air 1/2 the time. The temp gage is jumping up and down but never gets out of the range it should be in. I am confused.

These topics always seem to show up at the right time...

THREAD HIJACK!

I was thinking my heater could be pumping out warmer air. I considered the thermostat, water control valve, then possibly heater core.

Then I had a brain spasm, turned on the rear heater and it blows air almost hot enough to burn my fingers.

So, I'm thinking definitely the heater core under the dash, everyone agree? Maybe flush it or check for clogging? The radiator itself looks very good.

Rich J
 
Serious threadjack!

Once the heating systems on these babies are up to snuff, as was quoted by one of our sibs here, there's enough heat to melt a glacier. Stunning...I love it! Absolutely love it! (And I hate running temps above 72 or so inside the vehicle...but for tailgating...wow!)
 
Temp gauge jumping up and down sounds more like engine coolant level problems. You're heater core may be clogged, but sounds like you have other issues also.
 
Back flushing the heater core will do amazing stuff as long as it is pluged with debree. I would try this and see if the heater comes up to snuff. If not plan a weekend for this as you have to tear the dash apart(major hassle). I would also spend the money to buy a high quality core, not a cheap one. You really do not want to do this job more than once.
As for temp guage going up and down, it is not the heater that is creating that, sticking thermostat or fluid level too low, bad cap, etc. You have a problem that needs to be fixed before you hurt your engine and need more serious work. later robbie
 
See if you've got air in the system.
 
how much is a good heater core and where do you buy from?
 
I cured my intermittent heat on my 93 with a good coolant flush/back flush, follow e9999's post (cleaning the coolant system) in the FAQ for more info on how-to.
 

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