WahooSteeler Posted March 10, 2018 Share Posted March 10, 2018 Just recently temp gauge has been slowly creeping past 210 and ends up in the 240 range. At first I thought maybe bad temp sensor because I'd raise the hood and the engine bay was not putting off a ton of heat and there was no hissing or noise from near boil over. Drove it on an extended trip yesterday evening and although it never went in to the red it was just above it and when I got to my destination I raised the hood and the heater valve was spitting a little. Anyhoo, I've also noticed the last few times I raised the hood that the overflow tank level had not budged...........bad tstat? Link to comment Share on other sites More sharing options...
yxmj Posted March 10, 2018 Share Posted March 10, 2018 Or your water pump is on the way out....is it weeping from the hole on the bottom? Link to comment Share on other sites More sharing options...
WahooSteeler Posted March 10, 2018 Author Share Posted March 10, 2018 2 minutes ago, yxmj said: Or your water pump is on the way out....is it weeping from the hole on the bottom? Water pump just replaced, fan clutch, upper rad hose, heater control valve, coolant tank............. Link to comment Share on other sites More sharing options...
Ωhm Posted March 10, 2018 Share Posted March 10, 2018 4 hours ago, WahooSteeler said: the last few times I raised the hood that the overflow tank level had not budged..... Check hose between radiator and overflow bottle for blockage. Link to comment Share on other sites More sharing options...
yxmj Posted March 11, 2018 Share Posted March 11, 2018 To be clear....you still have the tank on the firewall?? Or if you have a rad with a cap.....maybe just the cap? Link to comment Share on other sites More sharing options...
WahooSteeler Posted March 11, 2018 Author Share Posted March 11, 2018 8 hours ago, yxmj said: To be clear....you still have the tank on the firewall?? Or if you have a rad with a cap.....maybe just the cap? OE closed system Link to comment Share on other sites More sharing options...
HOrnbrod Posted March 11, 2018 Share Posted March 11, 2018 How old is your radiator? Link to comment Share on other sites More sharing options...
WahooSteeler Posted March 11, 2018 Author Share Posted March 11, 2018 24 minutes ago, HOrnbrod said: How old is your radiator? I'm only the second owner but if I had to guess it's original and just turned 220k yesterday, so I'm realizing it could very well be the rad is finally shot. I've only put 10k on it in the 10yrs I've owned it and it was parked for a few years until last fall. It was the original owner's DD and overall it seemed like it was well taken care of when I bought it. I've never done a flush on it so I plan on doing that, and since a new tstat is inexpensive I plan on replacing it with a OE unit as you suggest or a Motorad fail-safe unit. It will be my 16yr old son's DD soon when I get this and a few other things fixed. Link to comment Share on other sites More sharing options...
HOrnbrod Posted March 11, 2018 Share Posted March 11, 2018 9 minutes ago, WahooSteeler said: I'm only the second owner but if I had to guess it's original and just turned 220k yesterday, so I'm realizing it could very well be the rad is finally shot. I've only put 10k on it in the 10yrs I've owned it and it was parked for a few years until last fall. It was the original owner's DD and overall it seemed like it was well taken care of when I bought it. I've never done a flush on it so I plan on doing that, and since a new tstat is inexpensive I plan on replacing it with a OE unit as you suggest or a Motorad fail-safe unit. It will be my 16yr old son's DD soon when I get this and a few other things fixed. The radiator should be replaced or at minimum professionally rodded out by a good shop and flow tested. The passageways are probably clogged nearly shut as old as it is, especially as it's been parked and not running for all those years. Link to comment Share on other sites More sharing options...
WahooSteeler Posted March 11, 2018 Author Share Posted March 11, 2018 10 minutes ago, HOrnbrod said: The radiator should be replaced or at minimum professionally rodded out by a good shop and flow tested. The passageways are probably clogged nearly shut as old as it is, especially as it's been parked and not running for all those years. I've seen lots of debate on replacement units and/or going to an open system. I'm generally of the opinion to spend a little more to get quality and do it right. Link to comment Share on other sites More sharing options...
WahooSteeler Posted March 12, 2018 Author Share Posted March 12, 2018 Gonna change out the tstat just to see what happens. Question.......going to use a Fel-pro paper gasket, do you guys recommend RTV with that? Link to comment Share on other sites More sharing options...
ShortBox88 Posted March 12, 2018 Share Posted March 12, 2018 18 minutes ago, WahooSteeler said: Gonna change out the tstat just to see what happens. Question.......going to use a Fel-pro paper gasket, do you guys recommend RTV with that? I always use a thin layer of RTV on each side of the gasket. I've been told that the blue RTV is best for contact with water, but not sure if there's any truth to that. Never had issues other than when I use too much of it and make a mess and cause the gasket to move around when tightening the bolts, etc... I seem to remember that at least one of the bolt holes tapped in the head for the thermostat housing is not a blind hole (so threaded all the way through into the head water jacket) so I would also recommend using a copper washer (like for a brakeline banjo bolt) on that bolt or use a thread sealer on the bolt threads - like permatex high temp thread sealant: https://www.permatex.com/products/thread-compounds/thread-sealants/permatex-high-temperature-thread-sealant/ Link to comment Share on other sites More sharing options...
omega_rugal Posted March 12, 2018 Share Posted March 12, 2018 try another sensor before you start taking the engine apart...a hot engine is easily recognizable because it`s... i don`t know... HOT? On 10/3/2018 at 12:45 PM, WahooSteeler said: heater valve was spitting a little the valve was leaking coolant? Link to comment Share on other sites More sharing options...
WahooSteeler Posted March 12, 2018 Author Share Posted March 12, 2018 40 minutes ago, omega_rugal said: try another sensor before you start taking the engine apart...a hot engine is easily recognizable because it`s... i don`t know... HOT? the valve was leaking coolant? Yes, and just confirmed that again this evening. Put in a new tstat with "jiggle valve" and got it up to temp. Took a solid 15mins before temp got to 230ish, overflow bottle never budged, upper radiator hose cold to the touch. Shut it down and while looking around saw steady dripping at heater valve. Link to comment Share on other sites More sharing options...
omega_rugal Posted March 12, 2018 Share Posted March 12, 2018 mmm seems coolant is not moving, are you sure you got the right water pump? how is the radiator? cold or hot? also, if the heater valve is leaking the system is not getting enough pressure to work... Link to comment Share on other sites More sharing options...
yxmj Posted March 12, 2018 Share Posted March 12, 2018 Or....you can test your water pump If you are 100% certain that you have the correct rotation pump on....there are reverse rotation pumps ..... Take the heater hose off of the water pump.. .put a chunk of scrap hose on it and please the end in a milk jug or pail....start the motor.....do you get a strong stream of water? Link to comment Share on other sites More sharing options...
Pete M Posted March 12, 2018 Share Posted March 12, 2018 just an fyi, you can swap in a later style radiator (with rad cap) and retain the closed system. I've had it for years. Link to comment Share on other sites More sharing options...
WahooSteeler Posted March 12, 2018 Author Share Posted March 12, 2018 Pete, other than the obvious advantage are there any disadvantages? Link to comment Share on other sites More sharing options...
WahooSteeler Posted March 12, 2018 Author Share Posted March 12, 2018 10 hours ago, WahooSteeler said: Yes, and just confirmed that again this evening. Put in a new tstat with "jiggle valve" and got it up to temp. Took a solid 15mins before temp got to 230ish, overflow bottle never budged, upper radiator hose cold to the touch. Shut it down and while looking around saw steady dripping at heater valve. Forgot to mention slightly critical item here.........when I changed out tstat I did not drain coolant and just pulled hoses from tstat housing expecting to lose some coolant but when I pulled them off there wasn't much coolant to speak of in the lines. Link to comment Share on other sites More sharing options...
Pete M Posted March 12, 2018 Share Posted March 12, 2018 49 minutes ago, WahooSteeler said: Pete, other than the obvious advantage are there any disadvantages? not that I've experienced. it's the same radiator, but with a little tube sticking out and a rad cap on it. In theory you should probably include an overflow bottle should the cap pop. I just routed a hose down to the bottom of the engine bay. conveniently circled in this old pic. Link to comment Share on other sites More sharing options...
WahooSteeler Posted March 12, 2018 Author Share Posted March 12, 2018 3 hours ago, Pete M said: not that I've experienced. it's the same radiator, but with a little tube sticking out and a rad cap on it. In theory you should probably include an overflow bottle should the cap pop. I just routed a hose down to the bottom of the engine bay. conveniently circled in this old pic. Pete, what year and model MJ or XJ would I search for this replacement? Also, my truck has the factory HD cooling and trans cooler. I like the ability to easily do a flush with having the cap. So do you still have the pressure bottle on the passenger side firewall though and the hose off the cap is just a pop-off valve? Link to comment Share on other sites More sharing options...
Pete M Posted March 12, 2018 Share Posted March 12, 2018 um, "late model"? I swapped it in like 20 years ago so I'm not certain. I have a feeling it's anything after the closed system was retired. Link to comment Share on other sites More sharing options...
yxmj Posted March 12, 2018 Share Posted March 12, 2018 I have a 2000 XJ rad in my 87 MJ....it fit like a glove.....you should be able to make any one work? Link to comment Share on other sites More sharing options...
WahooSteeler Posted March 12, 2018 Author Share Posted March 12, 2018 YXMJ, yeah, I think I'm resolved to getting one and converting to open system, eliminate heater valve etc. It seems that less is more with an open system, more consistent operating temps, easier to maintain/service. Came across a nice write-up in Four Wheeler mag from last summer where they converted an 89 XJ over and was essentially plug and play with new rad dropping right in etc. Being that I've already replaced all the mechanical components in the last couple of months it only makes sense to not only get a new rad as Hornbrod and others have suggested but to convert to an open system also. Link to comment Share on other sites More sharing options...
HOrnbrod Posted March 12, 2018 Share Posted March 12, 2018 Good move. Link to comment Share on other sites More sharing options...
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