Overheating Issue

[grantpremo@gmail.com]

Sorry if there are a lot of threads about this, I only looked back a few pages and didn't see anyone with similar issues.

So, my 2001 V6 Xterra has been overheating recently. It works fine around town, but when I get on the interstate, the temperature gauge starts to spike after a few miles. When I exit, it usually falls back down pretty quickly (with in a mile or so) when I'm driving at lower RPMs. I took it into the shop and they changed the thermostat (which was stuck), changed a few hoses, flushed the radiator, and resurfaced the cylinder heads. It still has the same problems though. It hasn't had any other problems besides this. The AC, transmission, ect all work fine.

Does anyone know what might be causing the overheating or what I should look into? I'm starting to get desperate.

[json3904]

well if they had you replace all that and they didnt find the problem i would go back and make them find it cause i know you paid some coin for all the work, and it sounds like it didnt need it other than the T-stat

[silverbullet]

Wow. they pulled the heads because it was overheating and machined them? there had to be another problem if they pulled the heads. Maybe a blown head gasket? how much was your invoice if you don't mind me asking?

I agree with Jason though. you shouldn't still be having a problem so I'd take it back and get them to fix it.

[grantpremo@gmail.com]

I'm definitely taking it back to the shop tomorrow, but I wanted to see if anyone had similar problems so I could pass that along. The bill was $1300, which I normally wouldn't go for, but I trust the shop and thought it would fix the problem, based on their advice. Needless to say, I won't be giving them another dime.

[Ricer-X]

man, i hate when mechanics just throw parts at a problem

[RawkerStatus]

yeah those aren't mechanics... they're part changers... a good mechanic will diagnose the problem with out having to change parts that aren't needed anywho.. other then that.. maybe you have an airbubble that gets stuck n it just reads high? idk not sure.

[Xterra Mike]

Yea i would say system isn't blead right. Took me 3 times to get all the air out. I had a head leak that was causing a misfire and overheating. I would say maybe bad flow in the radiator.

[roninjiro]

i had an overheating issue, but my fix was simple with installing a new t-stat and replaced the fan clutch. they should 'finish' repairing it at no cost imo.

[TJTJ]

If its overheating at speed, when airflow through the fins should be maximized, and the fan clutch would be disengaged, etc (not needed at high speed...)...but NOT at slower speeds, the problem is unlikely to be related to the fan.

If the coolant passages are clogged, they would allow sufficient flow at low engine speeds, and become critical orifices at high flow rates when engine rpm was higher.

This would mean that at high engine rpm, the engine could not shed enough heat...and would get hotter....but, when the rpm was low enough, enough coolant would flow to carry off the heat.

That would be my first guess as to a possible explanation.

After that, I'd consider frictional issues, as higher rpm generates more heat due to friction, etc. Perhaps this is where the head work came into play...except that didn't fix anything.



So - As a Plan A, consider coolant pathways, and possible constrictions.

An easy fix is a hose that collapses under suction, after that, clogged coolant journals, etc.

[Brokensandwich]

Did you ever get this problem resolved? I've been having the exact same issue. I've replaced the fan clutch, thermostat, knock sensor (probably unrelated) and a/c compressor. I replaced the radiator today but don't know if that solved the problem or not yet. I have the same issue where it the temp will shoot up when the RPMs are over 3500 but below that the temp is fine. I've been to 2 different shops and no one really has any concrete ideas.

Have you tried anything else?