So, stuff to check would be:
- Is your radiator clean on the outside (air passages)? Yes it is.
- Is your radiator clean on the inside? Maybe it needs to be rodded out.
I'm not sure about this one. I don't suppose there is a way to really know is there, except to pull the radiator and have it done. Are there any replacement radiators that guys have found to be beneficial? It seems that if I was going to pull the radiator I might as well replace it instead of having it cleaned out.
- Is the radiator core (fins) in ok shape?
Yes.
- Is your clutch fan working right? Might need new oil and the temperature adjusted?
I haven't checked this but have read about changing the silicone. Is there a test to know if it's necessary?
- Are your rad hoses old? They can collapse and stop coolant flow apparently when they are too soft.
No, they are all good. Steve Jackson replaced them all right before I bought the truck 18 months ago.
- Water pump been done recently?
Yes, along with timing belt, etc. just two months ago.
- How is your motor tuned? What are your EGTs? Boost? Fuel?
Stock boost since the intercooler charge tube failed and I disconnected it. I did turn up the fuel just about 1/3 of a turn.
- What rpms are you running when you hit hills? Running on flat ground down the four lane highway I'm running about 2500 rpm's with the overdrive engaged. When I hit hills and the speed dropped I would disengage the overdrive. That would keep the EGT's down but at higher revs the coolant temp would increase so I had to back off quite a bit. I have read where you've said to keep the RPM's up above 3k on hills but when I did that the coolant temps would climb fast.
- What are the ambient temps you were in?
70f for the most part. Not real hot.
- Did you have the A/C on? The factory computer will shut the A/C off on you when you are running the temperatures you are talking about. Did this happen to you? A/C will cause slightly higher coolant temps as well.
I mostly had the A/C on, and it never cut out on its own. I did have the A/C thermostat turned down low so it was cutting in and out because of that but not in any connection with coolant temps.
- Does your transmission lock-up work right? The transmission when out of lock-up will generate a huge amount of heat which it dumps into the radiator (factory trans cooler). Leave your transmission PWR switch OFF. I recommend never running it in PWR mode. Hit the hills in 3rd gear (OD off). You should get lock-up in 3rd gear at 70km/hr.
By PWR do you mean the ECT button? I drive with that engaged almost always. I think it just alters the shift points to a higher range in the RPM, correct? I haven't seen it make any difference once you're driving down the highway, just around town. But yes, the lock up works perfectly. No trouble with the tranny at all. I have also installed an external transmission cooler, which I can't see makes any difference that I can document but I like knowing it's there and helping to cool things a bit.
- Are you sure that your gauge is reading right? What was the factory gauge indicating before you went with an aftermarket gauge?
The stock gauge was almost always in the very top of the white, almost touching the red when going down the highway. Around town always in the middle somewhere. The actual temps I'm seeing on the new gauge do correspond with that, although there is no clear way to know if the specific temps its showing are correct. Again, I've never had any of the classic signs of an overheated engine. No loss of power, no ticking sounds of overheated metal, nothing strange going on with the cooling system when I stop and pop the hood and look it over after running on the highway.
- Get your intercooler working again. It'll help lower temps as well.
That's a sure thing. I tried some creative stuff that didn't pan out as I'd hoped but I will for sure get it going. It was just too big of a project to handle on the road. I can say that the 1,000 or so miles I drove with the intercooler functioning gave me lower EGT's for sure, but I didn't see a lot of difference in the coolant temps. Then when I put on the manual boost controller and got the boost up to about 15 pounds the egt's dropped a lot more but it blew out a charge tube...
- What brand thermostat are you running? I HIGHLY recommend running a Tridon high-flow thermostat. They work really well:
TRIDON HF Thermostat Hilux Surf(Diesel)LN130(G,W)Inc.Turbo 8/91-3/93 2.4L 2L-T,E | eBay
I will get one. I actually removed the thermostat for part of the trip just to experiment. No real difference with it out except the obvious slightly slower warm up time. Once up to temps and going down the highway it ran at the same temps with or without it. Remember, I've never had any overheating problems around town, sitting in traffic after a run on the highway, no problems like that at all. Cools down fast and does great all except at sustained speeds of 65mph.
I run Evans. Under normal driving conditions, it runs the same temperature as regular coolant in these motors.
When I tow (total vehicle trailer weight of at least 8500lbs!) up big hills (6% grade or more) in 90f+ ambient temps it does get hot. Up to 220-230f maximum. Initially it runs a little hotter than regular coolant would when I hit the hills. But where I'd run into boil over with regular coolant, the Evan's seems to get just a little hotter, and then plateau's and stops getting hotter. This is because the greater the temp difference between the radiator and ambient, the more efficient the cooling. So running a little hotter actually makes the cooling more efficient. Sort of like driving in cooler ambient weather makes the cooling more efficient also. It's all about the temperature differential between ambient and radiator.
