the1998sr5

I've posted a few times due to my frustrating overheating problem. I received a comment on t4r.com and I wanted to bring it up here to see if any thought I should explore this further.

4 runner overheating after driving about 40 mins, but only under heavy load (steap hills) or heavy traffic. I've replaced radiator, tstat, hoses coolant (water wetter), rad cap complete new exhaust. NO obvious HG signs.

So someone on the other forum asked about my trans.I don't know when its the fluid was changed last, but probably near 100k (not on my watch, bought it way past due)- and although it shifts fine - fluid is very dirty, not burnt but dirty. I'm afraid to change it and lose the clutch particals floating around.

Does anyone think the trans oil may be getting extra hot and heating the radiator causing me to get hot? (putting heater on brings it right down)

I'm near my wits end here and I'm getting a shop to pressure and leak down test the engine next week. It's like not being able to drive reliably and take it to the trails is ruining getting a 4runner in the first place!

wyoming9

iTrader: (1)

I would agree the long over due to be changed Transmission fluid will put more of a burden on the cooling system.

As the fluid breaks down less lubrication more heat

Your also sure the condenser is not full of dirt??
Blocking Air Flow.

Could be some of both.

the1998sr5

Hi wyoming9, thanks for following up, in fact- I've seen you post some great advice int he past.

The Condenser (Ac condenser correct) does not look dirty. I can see through it in all spots, its not caked or anything. And while I like to hit the trail, I'm pretty conservative- not a big mud bog guy or tough truck style driver. I'm stock with 31.4 inch mud tires and I've never put her in a position she could not get out of.

Again, New exhaust system, new rad cap, new rad, new flush (added water wetter), new t stat, new fan clutch, new fan>>> I'm starting to think HG and going to have it tested via leak down and block test.

Unfortunately, these tests, as I understand do not always detect leaks due to varying engine temps and so on.

The big problem for me is I'm on a limited budget and I have replace a HG or do a timing belt, that's all I can afford..I'd have to park it for a few months and put some more cash aside. SO I really need to nail this issue down, but I realize the chance of figuring this out on the cheap is slim.


Can anyone suggest a cheap temp gun and where I could take readings to try and trouble shoot this?

wyoming9

iTrader: (1)

I have seen some around for around $50.00

For that price not sure of quality.

Even Walmart sells them.

With the AC off and engine Thermostat open

Get readings of all different areas of the radiator

Look for major differences in temperature knowing the top should be warmer.

Your transmission would have to get warm before it starts dumping lots of heat into the cooling system.

Could this be a gauge problem as sending units do go bad with age?? As the resistance changes it is possible to give a false reading



Just what Thermostat and Cap Toyota??

The China made Stant products have been real junk.

If I recall your no where close to me I would be glad to help.

You are working on a 3.4?? While those head gaskets fail not as bad as the 3.0

How does the timing belt look ??

the1998sr5

I don't expect it to be a gauge issue because I have seen the coolant start to bubble up in the overflow tank. This never happened in the past and I've always checked my fluids pretty well.

All parts are from Toyota except the radiator which is Koyo, recommended by this forum.

I'm in Jersey City NJ, so not close enough to stop by (especially with this problem)- but I genuinely appreciate your help.

The timing belt is just about ready to be done it was changed at 150 and I'm at 180k now. My fear is that I change the timing belt/ water pump (or even HG) and I'm still overheating. I legitimately could throw 1500$ at this, but it seems like such a gamble now.

I know my pinion bearing is worn, it makes noise and I've checked with a stethoscope, is that a suspect here- or too minor to have a serious effect?

I will buy a good temp gun and take some readings. I feel the top and bottom hose rather often because I am keeping an eye on this and I must say, the bottom hose does not feel much cooler than the top hose.

At the end of the day its still a yota and it is getting me to and from work, so I'm thankful for what I've got! If I do not use the AC or get stuck in traffic it will run normal the whole trip.


Do you know any forum members in my neck of the woods that could help? Again I do have some money to spend, just want to spend it smart!

wyoming9

iTrader: (1)

You can have your coolant tested for hydrocarbons .

Your not losing large amounts of coolant yet??

a compression test should show a bad head gasket but you don`t have the white smoke like a smoke screen.

A engine with that many miles a leak down test might just show worn valves and rings.

Now that you said it only starts to get hot in traffic like Rush hour trying to get through the Lincoln Tunnel east bound after a multi car crash!!

When the AC is on both the condenser and the transmission are dumping heat into the radiator

To the point it no longer cools fast enough.

I Don`t know anyone that well over that way.

the1998sr5

Losing very small amount of coolant over course of a month, if any (like an inch in the overflow tank- radiator itself has never been low).

I'm going to get it tested at my local spot (very honest, but expensive and not the fastest moving crew) next Friday, I'll report back and provide feedback.

If anyone has any other ideas please let me know, I'm willing to investigate any leads!

Best,
a 4runner driver doing his best to remain optimistic