Isuzu SUV Forum banner
1 - 13 of 13 Posts

·
Premium Member
Joined
·
5,577 Posts
Discussion Starter · #1 ·
Today twice I had coolant overflow out of my overflow bottle on the 99 Rodeo. Once after an hour on the highway, then again after a 30 minute drive up a few percent grade.

After that I let it idle until the temp stabilized (at 183F). The overflow didn't overflow, not did the level in it change much.

On the trip home the temp touched 202 once under load, but was normally in the 190 range, even at 70 on the highway (with the same load).

I was moving a pretty good load with it, but I've done that before without incident.

Only 140k on this V6, I hope it isn't a head gasket. Any other ideas?

-Tad
 

·
Registered
Joined
·
5,475 Posts
Sounds like a headgasket to me....sorry.
 

·
Registered
Joined
·
1,623 Posts
Like RF says temp swings are indicative of HG failure but geez I have done some mean things to the 3.2 and 3.5 motors and not popped a gasket.

What about a old radiator or a weak cap?
 

·
Premium Member
Joined
·
5,577 Posts
Discussion Starter · #5 ·
I'll certainly try the rad cap first. Good idea. It is original.

The temp swings were normal, at least as compared to my 3.5 Trooper and the previous performance of this truck. The swings were directly related to increased and decreased loads due to hills.

-Td
 

·
Registered
Joined
·
347 Posts
This same thing just happened to me today. I didn't lose much... My temp gauge has never gone above operating temp though
 

·
Registered
Joined
·
1,623 Posts
Maybe I have never loaded mine that long/hard or maybe never had a sensitive enough gauge but mine seem to sit at the same spot on the temp gauge no matter if I am idling in freezing temps or running 90 mph when it is 100 degrees.

Regardless those temps are not that high. If it was 230 or so I would think more of head gasket but 202 on a 185-190 degree thermostat isn't high.
 

·
Premium Member
Joined
·
5,577 Posts
Discussion Starter · #10 ·
Could be dirty, but it has only 20k since new and has always run the long-life coolant (says it's good for 100k). I'll flush it after the cap test. Thanks.

-Tad
 

·
Registered
Joined
·
1,623 Posts
Tad said:
Yea, the temp gauge never moved, but my Scangauge tells me the exact temp.

Tad
Ok cool so really the only symptom most people would have seen is the blowing out of the tank and not a swinging temp gauge. Makes me even more suspicious of the cap.
 

·
Registered
Joined
·
397 Posts
My vote is radiator cap too. I've had the same thing happen.
 
1 - 13 of 13 Posts
Top