Hey y'all, need a little help with this coolant valve at the top of the firewall, see pick. Looks like either the hose tore or the plastic broke on the house end. I didn't notice until it was too late, engine shut down after high temps. My question is if this is a common problem and if it's a simple replace that valve and hope for no head gasket damage or warpage? Thanks

picture link

Heater control valve.

Simple to replace.

Try it, and see what your engine does.

If it keeps overheating, do a leak down test.


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Yup, heater control valve. Fairly common for them to leak/break after 20ish years. It's a good idea to replace those as preventative maintenance before they fail.

As for your engine, if you overheated it to the point that it shut down, it's probably not good. Fill it back up with coolant and see what happens.

Before you spend money on a valve just to find out your motor is junk remove the hose from the other side of the valve and join the 2 hoses together.

Then you can run it.

FYI next time.

A 75 dollar ultra gauge lets you set temp alarms. You could have been alerted before it got too hot.

This should be the first mod any of us do. Best money you can spend.

Sorry for your loss.

^X2 on the Ultragauge recommendation. The settable alarms that the unit provides is invaluable especially in a overheat situation.

Thanks y'all, lots of good advice and ideas. I'll keep yall updated, I was eventually thinking v8 swap but might have to accelerate those plans...

Also, for testing the engine by bypassing the control valve, what would yall use to connect the two hoses together?

Thanks again!

Just go to a hardware store and buy a male to male fitting of the correct size. Make sure it is long enough to connect the two ends together.

X3 on the Ultragauge with temp alarms, money well spent.

If you bypass the valve, keep in mind some coolant will not flow into the radiator and engine might run bit hot. Since we are heading into cold weather, this might not affect you at present.

I replaced this valve with an OEM unit few months ago after noticing some wear on the inlet tube on the old unit. Amayama had it for a decent price.

Little update, I bypassed the heater valve as suggested and filed the radiator and ran it to see if there are any leaks. I got the temp up to almost 200 and after about 30 a, no leaks!

I'll take some picks and post up what I used for the bypass tube for others. So far, looks like I got lucky, I'll order a new valve and hoses and flush the coolant. Thanks for the help!

How does it run?
Did you do a compression test?
Any oil getting into the rad or water getting into the crankcase?

It sounds like you had a severe overheat, you may not be out of the woods yet.

Ran fine, but I didn't drive it around. I'll check for oil when I flush the coolant. So far, no coolant in the oil so that's at least good. Good point about compression test, will also check on that. Thanks!

I was just checking out the Ultragauge website and I see they have 3 different versions available. Does anyone know what the best version is for a 1997 4runner?

Not sure what all features would be available with each unit for this year 4runner or which one to buy. Appreciate any help from anyone that owns one or would know.

I'm thinking of going with the UltraGauge EM Plus for my 97 manual. I don't think that the 3rd gen can use the extra parameters on the UltraGauge MX. Somebody please correct me if I am wrong about that. The UltraGauge Blue connects to your phone and I don't like that because I use my phone to stream music. I don't want to juggle in between music and scanning all the time and I like the idea of being able to look right at a mounted gauge.

I did some more research and yes that's the conclusion I came to also. The added feature the MX offers that I was interested in was the transmission temp because mine is an automatic but with 97 I found out that data is not available. The later 3rd Gens and I'm not sure what year it starts but transmission temp is available so the MX could be something to consider if someone has an 02 (and possibly an 01 I don't really know) but it seems it require a bunch of manufacturer codes. I found the codes on the scangauge site (a competitors product for those not familiar). So I'm ordering the EM plus for my 97.

I'd research before buying the MX though even if you have an 02, seems it could get complicated setting it up.