jjenks0

My 90 4 runner has the great 3.0 and I have owned it for a couple of years. As my memory is not what it use to be I seem to remember that it use to heat up fairly quickly but for the past winter the I drive 13 miles to work and the needle barely comes off the cold mark. Of course when you shut the engine down and then start it back up the needle is half way because the the cooling system was not active. I replaced the thermostate a month ago and the old one seemed fine and even put cardboard in front of the radiator. The cab heater puts out luke warm air,

I have had the engine out two summers ago to do the famous valve job, took the heater core out last summer because I thought it was leaking but ended up the hoses leading to it were loose. I am wondering if I got some hoses in the wrong place that allows the water to bypass the thermostate.

Anyone got any ideas?

Thanks.

Jenks

Elton

did you use a oem t stat ? it should have a little hole drilled on it

jjenks0

No I did not. Do you think that would make that big of a difference? I will pick one up today.

Elton

so did this problem start with a new t stat ?

purerockfury

I had a similar problem w/ my old 4Runner. It had
a 22re in it, but this might work as well.

I drilled a 3/16" hole in my after market thermostat.
Problem was solved. Got great heat and ran perfect.

Or you can buy a dual stage thermostat for like $60.00.

Hope this helps, good luck.

thook

I'm almost positive the dual stage/little hole thing/issue is only related to the 22re.

My '92 heats up very quickly, and so should yours....without a dual stage/little hole. Just a regular from NAPA. I've read, and I believe, it's due to the location of the t-stat being right after the radiator and not up on the top where the coolant has a distance to travel and therefore heating up slower. Something to that effect.

Anyway, how old is your water pump?

jjenks0

The problem was before the thermostate, may have started when I did the valves and replaced the original thermostate with after market. I think the old one had the hole because I kinda remember thinking that was odd.

I do not know how old the water pump is. Would that make a difference on the engine not getting hot?

Thanks.

Jenks

thook

Generally, no. If it doesn't circulate coolant properly, it causes overheating. But, if it's leaking, it can allow air into the system which could cause the thermo to stick open.

However...
Since the thermo is right after the radiator on the 3.0, I'd make sure coolant flowing through the radiator with no air bubbles and that you installed the thermo correctly. And, that it is rated for the correct operating temp.

jjenks0

I am guessing the hole goes up on the thermostate.

thook

I'm not sure I understand what you're asking. Are you asking how the thermostat goes in? The spring side goes towards the motor, in that case.

jjenks0

no, the little hole drilled in the thermostate

thook

Still not sure what you mean, but I'll try.

It doesn't matter what position the hole is in....12o'clock, 6o'clock, etc.