Cherokee is Underheating
Herp Derp Jerp
Joined: Nov 2011
Posts: 18,251
Likes: 17
From: Parham, ON
Year: 1999
Model: Cherokee
Engine: 4.0L OBD-II
Seems fine. I wouldn't suspect a fan clutch anyway, at driving speed the 4.0L has enough heat to keep itself warm with a wide-open front grille and wind slamming into it at 60MPH (or whatever) - as long as coolant isn't entering the rad.
Thread Starter
Seasoned Member
Joined: Oct 2013
Posts: 376
Likes: 5
From: Idaho
Year: 1991
Model: Cherokee
Engine: 4.0 Liter
I wouldn't have thought so. When I pulled the upper radiator hose yesterday it was empty, there was a little but of coolant in the thermostat housing. So it don't think coolant is entering the radiator
Seasoned Member
Joined: Apr 2012
Posts: 402
Likes: 2
From: East Texas
Year: 98
Model: Cherokee
Engine: 4.0
i am absolutely sure that any vehicle with a properly working thermostat has no use for freakin' cardboard in front of the radiator. Think about it for a second. I don't know how many times i can say this or how many different ways, but if your thermostat is closed (as it should be before your engine reaches proper operating temperature) coolant doesn't flow through your radiator. So what good is putting cardboard in front of it going to do? Absolutely none.
Some of you need a few classes at your local vocational technical college instead of depending on what joe bob taught your dad 40 years ago.
I am out of this thread. Ya'll put some cardboard in front of those radiators and enjoy. You'll look cool just like the truckers. Don't forget those stinger bumpers and led light bars too.
Some of you need a few classes at your local vocational technical college instead of depending on what joe bob taught your dad 40 years ago.
I am out of this thread. Ya'll put some cardboard in front of those radiators and enjoy. You'll look cool just like the truckers. Don't forget those stinger bumpers and led light bars too.
Thread Starter
Seasoned Member
Joined: Oct 2013
Posts: 376
Likes: 5
From: Idaho
Year: 1991
Model: Cherokee
Engine: 4.0 Liter
Okay so here's where I'm at. Today I pulled off my upper radiator hose, and fired up the engine. Now my understanding is that the thermostat should have a 100% seal and coolant should not come through until the thermostat begins to open, correct? After firing up the engine from dead cold, coolant came through the thermostat and filled up the housing. It's pretty obvious that this is what is causing my underheating issue. The question now is, why is it leaking? I figure I'll try another Mopar thermostat, now I've seen people who have got the one with 3 gaskets? Is this needed? Do the other gaskets play a role in the thermostat sealing against the housing? I've found many places to buy just the thermostat however I couldn't find anywhere that sold the Mopar thermostat with the 3 gaskets and unfortunately I don't have a local dealer.
On a separate note, Salad I checked the gaps on the plugs and they're all gapped properly. While I was at it I did a compression test and it was great. So I'm happy about that.
On a separate note, Salad I checked the gaps on the plugs and they're all gapped properly. While I was at it I did a compression test and it was great. So I'm happy about that.
CF Veteran
Joined: Nov 2008
Posts: 1,077
Likes: 23
From: Herndon, VA
Year: 1996
Model: Cherokee
Engine: 4.0
Seems like me and my high horse were f***ing correct. Shame I had you on ignore and just now saw this.
Last edited by robertj; Feb 24, 2016 at 04:24 PM.
Thread Starter
Seasoned Member
Joined: Oct 2013
Posts: 376
Likes: 5
From: Idaho
Year: 1991
Model: Cherokee
Engine: 4.0 Liter
Well I guess thinking that there's never been a bad Mopar thermostat was extremely incorrect of me. I'll just be happy to get it fixed finally. I do try and troubleshoot beforehand, and use proper fixes because as we all eventually realize, buying cheap makes everything more expensive in the long run.
CF ADMIN
Joined: Sep 2010
Posts: 34,088
Likes: 257
From: Lantana, Fl
Year: 1996
Model: Cherokee (XJ)
Engine: 4.Slow
OK, I'm just gonna ask what EVERYONE here at CF is thinking right now. Why in the hell did you attempt this while the engine is running?!. You do realize that's why there is a Do Not Touch/Shut engine off before servicing decal right?
I hope you recover ok and this could have been a lot worse than it is. Consider yourself lucky.
I hope you recover ok and this could have been a lot worse than it is. Consider yourself lucky.
Beach Bum
Joined: Jul 2011
Posts: 6,123
Likes: 22
From: Cape Hatteras, North Carolina
Year: 2000 WJ
Model: Grand Cherokee
Engine: 4.0
Fan Shroud
Do you have a fan shroud for it? It is a very important safety item, and necessary for proper function of cooling system.
