I noticed my water temp gauge spiking about 5 minutes after initial startup. It goes up about 3/4 of the way, never gets redlined, but gets hotter than normal, and then goes back down to normal, which is a little less than halfway. It did it this morning and on the way home from work, both the same each time. Once it spikes, runs fine after that with no issues.

I recently pulled the heater core (all the HVAC) and the hoses and rerouted the return line to the feed line right before where it used to go into the heater core. I'll clean all that up later.

Here are some possible causes/solutions:

air pocket in coolant system from removing hoses/heater core and low on coolatn - I checked it and it is full so it will work itself out

t-stat sticking - r/r

t-stat sticking because of debris in system - flush system

Any diagnosis and advice is appreciated.

 

Bump

 

That to me sounds like a t-stat. I say that because it spikes then corrects itself. Behaves like the t-stat is either sticking closed or somehow having trouble opening. Once it opens, the system cools properly. Just my thoughts.

 

do the dual stage t-stat

www.4crawler.com

 

http://www.4crawler.com/4x4/CheapTri...tml#Thermostat

This sounds exactly what mine is doing...but it only started doing it AFTER I removed the heater core and looped the system. Hmmmm...

 

I'm not familiar with the 22RE cooling routing, but could the looping of the system be causing the coolant to flow fast through the heater core loop and put some sort of pressure on the t-stat which holds it closed. Finally the system builds up pressure though heat and blows the t-stat open? Just taking a wild guess here.

 

I'm going to cap off the feed/return lines by blinding off one side and taking the other side off, cutting it past the sensor nipple and welding it up. Then no more loop. If that doesn't fix the t-stat issue, then I'll put in the 2 valve t-stat and I'll have no more loop anyway...as I don't need it w/ no heater. Just something else to leak.

 

The cooling system is *very* sensitive to this "problem" from what I have observed. Mine used to be fine, then I made some small change and the problem showed up. Since installing the 2-valve t-stat, has never showed up again. The new t-stat is a superior design to the original 1-valve unit, it works very good, maintains a much more stable temperature and lasts a *long* time. Smaller slugs on the two t-stat valves respond to temp changes much faster than the single large slug and you get a built-in redundancy with the two valves.

 

where do you get these 2 valve t-stats?

 

Part # of 4Crawler's website above. At the dealer.

 

yeah they jacked up the price though... its now like $38

it works awesoem though... enver had any issues since i put mine in...

the stock tstat i had before i put in the 2 stage was only 3 months old before it failed!

 

Yep, dealer parts counter is where I got mine:
http://www.4crawler.com/4x4/CheapTri...tml#Thermostat

I've had mine in 6-7 years now, still going strong. I did pick up a spare a few years back, but have not needed to install it.

 

Mine is doing the excact same thing right now. the only thing i have touched on the cooling system is the throttle body part, I took it off to clean it and lost a little coolant.

dual thermo is on the list of things to do now!

wade

 

Don't ask me why, but since I took out the heater loop completely...all that stuff...and just ran a 6" hose from the intake to the return it doesn't spike anymore.

If it acts up again, or I have to replace it, I'll got to the new 2-valve t-stat.