98 V6 overheating on hills. Or is it?

L

Lizard333

New member
My 98 Limited has 148K on it. Just did the T-stat, water pump, t-belt, seals ect. To the best of my knowledge, all maintenance has been done that can be done to get this truck up to par, not knowing the previous history of the truck. Pulling a trailer from 1500 feet elevation to 7000 elevation, weighing 3500 pounds, the last 1500 feet I overheated. I know this because I have an Ultragauge II, and I got to 250. I pulled over and got her to cool down and made it home. BTW, I live at 7000 feet in AZ, so the temps don't get above 90 very often the summer time.

Thing is, putting around town, she doesn't get above 185. Under load is the only time I have the issue. If I am on the freeway pulling even moderate hills, the temp will start to climb slowly to the 210-220. So, is she overheating or is this normal. I realize I have become hyper conscious of the temps now after she overheated the first time, but should I be alarmed? I know Chevy vehicles run at 210 as normal operating temps, but I have found she stays at 185 normally, without load.

I did a search but didn't come up with much. I am considering replace the Radiotor cap, as it looked good and didn't bother when I did all of the other maintenance. I also have bypassed the transmission cooler in the radiator and went with an external one to avoid the Pink Milkshake issue.

Any help would be great. Even if it just to tell me that I am a dumb a$$ and not to worry.:pound:
 
Register to hide this ad
Test and/or replace

that rad cap. That could easily not be holding 16psi and letting the temps run too high. IMO anything above 220 is getting hot, it is not designed to do that, bad for the hardware and fluids involved. Luck! :banana:
 
Replace the radiator.
Drain the coolant and inspect the water lines inside the radiator. I am quite confident they are clogged on the top.

I had the same experience back in 2011... winter was all fine and just at the beginning of summer while heading up a hill made the temp gauge to go up. Thankfully I caught it, pulled it over, allowed to cool and saw I need a new radiator.... All solved!!!
 
I had the same issue towing a small car 1500 lbs up the local grade. it overheated and shortly after ended up replacing the radiator complete .problem is ,that now i have lost confidence in its ability to tow any loads up hill. i haven't owned the truck very long so i don't know if its just getting tired or thats all its capable of .does great around town and when not under a tow load .Idk?
 
I was going through the same thing a while back, when going up hill I overheated- turns out my fan clutch was faulty and my radiator lines were clogged. Replaced both, and did a trans flush put in a new trans filter. Haven't had any problems since.

I still need to get an external trans cooler and bypass the radiator just to be on the safe side.
 
Yes ,i did both .I replaced radiator ,t-stat ,hoses ,flush as well as the tranny .don't get me wrong as i love driving the truck and for getting around.its just after getting stuck with a load in tow i am a bit reluctant to roll the dice again ,is alll .my truck feels like its running strong but i have only owned it for a few years now and haven't towed with it but a few times .it might be relevant to the load i was towing because a 1500lb car + trailer is getting up there weight wise for a 3000+ tow vehicle.plus the local grade aint no joke ! maybe i'm also just paranoid after being stuck.
 
Last edited:
That's just an unfortunate reality of towing with an underpowered vehicle. I had the same issue towing two dirtbikes on a small trailer back home in the WY mountains. Altogether the total weight was probably only around 1200 lbs. I was at around 8000 ft and it was close to 90 that day, and my radiator cap literally blew off. Since then I have replaced the radiator with a new Denso unit. You can do a new radiator, trans cooler, and lines as everyone else mentioned. But the little 3.4 will always struggle towing at high elevations. You loose around 3% of your power every 1000 feet you go up in elevation. At 7000 ft that puts hp at around 145, and tq at around 175. That's not much power for a 5500 lb vehicle to tow 3500 addition lbs up hill.
 
Ok. I figured out the problem. The previous owner was less than stellar on maintenance. My radiator was clogged. This is why it started to overheat only after putting her through her paces. I dislodged enough crap to reduce the efficiency. This caused my overheating on the hills and under load.

A new radiator and the problem was fixed. 60$ to cook my existing radiator, or 90$ for a new one.
 
See I told ya!

nissanh said:
Replace the radiator.
Drain the coolant and inspect the water lines inside the radiator. I am quite confident they are clogged on the top.

I had the same experience back in 2011... winter was all fine and just at the beginning of summer while heading up a hill made the temp gauge to go up. Thankfully I caught it, pulled it over, allowed to cool and saw I need a new radiator.... All solved!!!
Click to expand...

I told ya!
 
Glad you found the issue. Last July, I was headed up to Lake Knoll with a fully loaded Runner. With the A/C on and pushing 65, the engine hit 218. That was enough to worry me. (Intake temp was 141, just fyi)

You're lucky that hitting 250 didn't warp anything.

Has anyone added a secondary fan for hard treks like this? I've been contemplating it for a while. Just adding a pusher fan to the front.
 
JBurt said:
Another thought is a bigger radiator. Anyone know of one that would fit?
Click to expand...

I've wondered the same thing. I'd like to know since I need to replace my radiator soon anyways (I'm assuming it's the original and I have 250k miles on the odo).
 
You guys are great. I post here to help others. I used the advice. Then I get chastised for not thanking the individual out in public for all to see. So I guess I should also bag on the others who's suggestion was was not the fix???

Not the first time the group here has been an ass to people new to this forum.
 
I was going to say Radiator also. I see this on a almost daily basis in my familys Radiator Shop. It is only under a load when the temps get into the red= some one is running a stop leak in it or nothing but water. The minerals in water after long times will turn a Radiator into a rock and even when we try and rod them out it will not budge at all. A lot of times we can hit it with the flush gun and they will open up and other times they are down. It sounded like your Radiator could have been saved but at that point of putting labor into a clean and flush it is almost the same price to get a new one either a Denso or a CPI Radiator with a lifetime warranty.

Blue
 
glad it was just the radiator. FWIW, i used to pull a double pwc trailer, ~2500lbs loaded + 6-700lbs of gear in the 4runner going to and from school, up the grapevine in CA when in 100* heat. I would run it 3500-4000rpm, it would get to 208 at the worst.

You should not have been getting to 250*. Glad you got it fixed.
 
You must log in or register to reply here.

Members online

Total: 533 (members: 2, guests: 531)

Forum statistics

Threads
278,316
Messages
3,554,106
Members
248,016
Latest member
Advally Service

Share this page

Trending content

Back
Top