I'm at my absolute wits end- truck still overheating despite best efforts (1 Viewer)

[baggar11]

If your fan is locked on all the time and you've verified your tstat is opening, I swear you need a new radiator.

Like I said way back early in this thread, I had a koyo 3 row that most people have good results with. But mine was bunk.

As of late, with my new radiator, ambient temps are 93-95F out and my coolant temps never see over 183F while idling all day long.

 

[DARKNESS]

Fan could be running as hard as you want but if the setup (size,fit within shroud) isn't right it won't matter how good the radiator is.

 

[surfpig]

I believe Beno said that quite a few 80s are set at around 7 for timing and they run fine. I pulled mine tonight and it is around 7. I may try setting it to 3 to see if it helps my issue. Then again for years mine has been set to 7. So why an issue all of a sudden?

Just chiming in, my timing is set at 6*. I just finished a roadtrip in mostly 100+ temps and coolant temp only topped 200* one time, climbing a steep grade. I have to think that something is blocking flow somewhere...

 

[jeffro109]

That's pretty warm for 80 ambient and sitting idle, I am usually at 186ish 190 tops even in 90 ambient.

Let know if you want to try a fan swap, we can see if you run cooler and I run hotter.

...Misspelled via IH8MUD app

Yeah, 197 is too high for idle at 80F. I can idle (no SC, moded fan clutch, ~5 yr old OEM rad/Toyo red/hoses, etc original water pump) as long as I care to and be at 186-190, never higher. This is ambient up to 85-90F or so.

Joey, yours seems to be acting like mine did when my original fan clutch crapped the bed and I put the modded one in.

Do the freaking huge fan experiment so we know if its water or air flow to trace down....

 

[thatcabledude]

Fan could be running as hard as you want but if the setup (size,fit within shroud) isn't right it won't matter how good the radiator is.

This is what I am thinking as well.

I have mentioned it twice, but no reply. I'm figuring that the fan may be too close to the radiator.

 

[DudeAbides]

Wasn't he having these problems before he even put the SC on?

 

[NLXTACY]

Wasn't he having these problems before he even put the SC on?

yes

 

[NLXTACY]

Ok so current info to confuse and annoy...

Its currently 72º outside. Just drove the truck about 10 miles and did two stops to run errands (to allow for heat soak). Coolant temp never ran above 193º. Nothing shocking. Its cool outside.

• Pulled inside my garage. Hood up and idling it stayed at 193º.
• Checked my timing, I was at 0º. I changed it to 3º.
• Truck sat idling for 20 minutes, no over heating. Stayed at 193º
• Checked my fan clutch by using a roll of shop towels, the fan just tore the roll to shreds. Would not stop.
• Turned on the JDM fan and I could actually feel additional air being pushed thru the radiator, did nothing to coolant temp.
• While in park, rev'd motor to 2500 rpm for 90 seconds. Coolant temp dropped to 186º

Side note: when I started the truck this morning from cold, there fan clutch did NOT roar. This is the first time I noticed it BUT I am starting it at 72º when I typically start the truck when its 90+

 

[NLXTACY]

I have mentioned it twice, but no reply. I'm figuring that the fan may be too close to the radiator.

Ask what? Is the fan too close? Who knows? Certainly not either of us. Its all speculation still.

 

[NLXTACY]

The things I am asking myself is:

Is the engine bay heat excessive?

Just drove it around and then let sit idle for 20 mins. Its currently 72º here in West Hills and the engine bay heat does not feel excessive. That all changes when the ambient approaches 100.

brainfarts:
I am now thinking the egr system and/or cats- something in there might be clogged/non functional
motor is basically a giant air pump. if the exhaust is somehow clogged, heat will back up into the motor.
just ideas....

The temperature readings I posted yesterday do not point to a blockage in the exhaust.

I thought Joey was overheating under load, and cools down at idle/ no load?

Well typically its opposite. I need to get onto the frwy to get the truck to cool down.

 

[NLXTACY]

Have you checked your transmission temp ? Could it be overheating the whole system ?

Have not. I used to have a gauge but can't recall why I removed it. There is no AT lights coming on so I don't think the trans is having any issues.

 

[94SRUNNER]

Shroud reinstalled?

 

[NLXTACY]

Did you try bringing the revs up and listen for the fan??

Did so this morning. At 72º ambient and at 2500 RPMs, with truck parked, the temps dropped from 193º to 186ª. Fan is "always on".

 

[NLXTACY]

Just wanted to add a thought. Do you suppose your engine might be suffering from retarded timing? This will cause overheating more than over advanced timing. Perhaps bad vacuum advance? Probably a stretch but just a thought. I do feel that it's gotta be either timing or backed up exhaust. Sorry for your troubles

The truck was at 0º when I just checked it. I adjusted it to 3º just now.

 

[NLXTACY]

I think it does chase. The gap between the ran blades and the shroud is needed to "seal" the. Two and ensure that there is no ciculatiob effect. With the higher density rad core there is more resistance to air flow at idle and a greater chance of this recirculation effect. It's where air will travel along the inner surface of the shroud nd then get expelled out the back. The worst case would be removing the shroud all together.

The shroud has been off for three days now.

 

[Bob_Garrett]

FWIW, I will throw in my data to add to the mix. We drove into San Diego from Tucson yesterday on I-8.

Current truck setup

1995 w/ SC 200k mi
35s, 4:56 gears, ARB bumper w/warn 12k winch, TJM rear bumper w/ tire carrier
94 3-core brass rad
Blue hub fan clutch w/10k fluid
3FE fan
Aux Hayden electric fan
Toyota red coolant 50/50 mix
Toyota OEM thermostat

At 95-100 F ambient, temps run 190-193 at freeway speed on level ground and about the same at idle. During the climb over the mountains going to San Diego with a starting ambient temp of 101, the temp maxed out at 202. The rig was fairly heavily loaded, probably and additional 400-500lbs of weight over its normal load.

 

[NLXTACY]

Do you have access to a very large blower fan (like the ones you seen at dyno tuning shops)? I wonder if artificially forcing air through the radiator when the engine is hot and the truck is sitting at idle with high ambient temps will move the coolant temp down. If it does then we know it's an airflow issue related to the fan itself. Iirc the problem is not there as long as the truck is moving at highway speed so this would eliminate head gasket and radiator sizing.

I do not.

 

[NLXTACY]

-I'm ignoring the cooling parts <assume all is new>

Yes, all new except heater core.

-checking cats- engine should be running at around 2K rpms or so when you check temps w/ IR gun.

Hmm, well I checked at idle. I will need to check again at 2k.

-additional coolant lines for various accessories may have changed the flow rate through the system negatively.

Not applicable yet since I didn't do the big mods yet because I wanted to solve this issue. I have the purge valve which is just a T to a short hose. I also block off the throttle body coolant line. Neither would negatively affect flow.

-adding a seperate tranny cooler away from the radiator may help by taking load off the radiator.
(however, it feels a bit like you are addressing a symptom rather than root cause)

I am considering this but I do agree its a symptom.

-there may be a cumalative effect of many things (i.e., clogging cats+egr/sensor issue+additional accessories) that combine to overheat

Perhaps but there all no other symptoms except for heat at high ambient.

-ignition timing checked? stock is 3º I think

Timing adjusted. Was 0º and changed to 3º

-i have to believe all your vac hoses/ egr and possible broken/clogged tubes have been replaced

All 100%. I chased a PO401 for a long time so I replaced PLENTY.

 

[NLXTACY]

When you are at idle and the temp is peaking is the transmission in gear? What are you getting for MPG figures?

When its peaking its either in D but stopped at a light or in P in my driveway. I won't know about MPG til I get closer to emptying this tank of gas. From what I can tell it has NOT been negatively affected.

 

[NLXTACY]

Fan could be running as hard as you want but if the setup (size,fit within shroud) isn't right it won't matter how good the radiator is.

As a reminder, I am running no shroud and the 17" fan. I will be testing both other fans soon.