Project "The Gray Goose"

[Goose_XJ88]

ok got a cooling (not getting hot enough) problem. Temp gauge was reading 110 deg (or whatever the unmarked line is) max. So i thought it was my thermostat stuck open bc i was getting bad mpg. Bought a mopar replacement and got that installed tonight. Got the jeep idling in the garage for 20min and multiple revs to 3k/holding revs at 2k and still no change in the temp gauge. Still reads 110 max.

All the hoses, and valve cover were hot to the touch but still 110*. Didnt think to check hose temp while warming up to see if the new thermostat stayed closed or not. Also have not "properly" burped the system but i thought air would cause overheating. All i want is the jeep to work at operating temp so i can get more than 8mpg.... HELP!!

Also should mention that i dont have an e-fan hooked up currently and my temps used to get past 210* and work as it should.

 

[BigKintheXJ]

Have you verified the temp with some other gauge?

 

[blondejoncherokee]

its cold outside. Could be air in the system too but it would read hotter not colder.

Try an IR gun at various places on the motor and cooling system.

Sending unit could be bad.

 

[GordoSmasho]

My money is on the sending unit.

 

[Goose_XJ88]

So if i have a faulty sending unit making the gauge read low, would that cause the computer to richen the fuel mixture causing bad MPG even if the temps are at 210?

I have not tried verifying the temp with another source. Will try to track down an IR gun to use tonight.

 

[GordoSmasho]

Yes indeed. That would mean the ecu is seeing the same temp. Also logic would suddest we have such a problem keeping these engines cool that i would highly doubt it was really running that cold. Even with the stat stuck open

 

[blondejoncherokee]

on a renix the sending unit and the coolant temp sensor are separate. engine gets one reading, gauge gets another

is that the case on the HO?

 

[Goose_XJ88]

Well mine is a renix so if temps are checking out normal 210*, do I need both the sending unit and temp sensor since the gauge would be reading wrong?? Reason I thought my first thermostat had been stuck open was that last summer, the temp would climb to 220 or so and my e-fan would kick on but not very often.

I do have a metal overflow tank which got super hot last night which seemed normal IIRC. I will try and track down a lazer temp and test different areas in the engine bay tonight.

 

[blondejoncherokee]

As I said above, they are separate. If the gauge is wrong then replace the sending unit. If the gauge is correct - via verification with a temp gun- then figure out why its running so cool (maybe thermostat is stuck open)

if its running super rich and reading open loop, then consider swapping out the coolant temp sensor if it doesn't read within spec on a multimeter.

 

[831_xj]

Harbor freight hasthem. Often on sale

 

[Goose_XJ88]

Ok. Havnt bought a temp gun yet but I think the thermostat is working properly. Heater hose and water pump hose were both hot to the touch while large upper radiator hose was still cold. Little bit later the radiator hose was hot.

I have a HO thermo housing with an aftermarket temp sensor up front. That digital temp gage reads about 206* when at a constant 2k rpm. That is a guess tho since the a lot of the lights in the gage aren't working. Iirc, the front of the block should read hotter than the rear of the block but it shouldn't be that far off. Based on the Jon's info, I presume my issues lie with the sending unit. This sound right?

 

[blondejoncherokee]

wait - what?
so you say its reading 110 and now you say 206* ? Which is it? It sounds like you have 2 gauges, one reads 110 and one reads 206? I would believe the 206 one at this point.

Rear is usually hotter than the front. Especially if you have exhaust leaks...

 

[Goose_XJ88]

Sorry Jon, Yes I have 2 gauges. One is aftermarket in the thermostat housing reading 205-206 (digital with lights screwed) and then the factory renix in the back of the block (factory gauge) which reads the unmarked line between 100 and 210.

 

[blondejoncherokee]

If you have 2 guages and neither shows over heating i would leave it. IR guns are cheap at HF if you need a third opinion.

 

[Goose_XJ88]

Problem is that Im getting like 8mpg and it used to be much better. My gauges also were working properly prior to last season. Im just now getting around to doing it...

 

[blondejoncherokee]

sounds like either o2 sensor or coolant temp sensor.

 

[Johnnie Walker]

I think lunghd or other have a chart of what the cts, the one in the block, should be at resistance wise pending temp. I would check that out before replacing. Also, check iat sensor in intake mani. Test is the same as cts

 

[Goose_XJ88]

Ok so I know most people are busy working on their rigs getting ready for Reno as am I. But, does anyone in the Sacramento area have time to help me get finished on my rig? Either today or tomorrow after work? I don't have much to really do but not all that much time or knowledge.

-torque all nuts
-install front axle shafts and fill d30
-bleed brakes
-slide fixed LCA forward in sliding adjustment upper mount
-driveway alignment
-install and wire up e-fan

Really the main pieces I need help with are the alignment, brakesand sliding the LCA 1/2". Also if anyone has a spread sheet with all the torque requirements that would be awesome. Right now the front end is up on jack stands so it is stuck in my garage in north east sac; near I80 and Madison.

 

[Goose_XJ88]

Small update on the Gray Goose as far as progress goes

-New rims, rock rings, and 33" MTR-K
-New ball joints installed
-New TREs installed
-Diff guard repainted and fairly straightened out
-Replaced chrome d30 diff cover with stock cover
-New fluid in d30
-Replaced thermostat
-10 blade E-fan upgrade

Soon to have proper alignment and brakes bleed.

Will post pictures after I get back from Reno

 

[XJensen]

Small update on the Gray Goose as far as progress goes

-New rims, rock rings, and 33" MTR-K
-New ball joints installed
-New TREs installed
-Diff guard repainted and fairly straightened out
-Replaced chrome d30 diff cover with stock cover
-New fluid in d30
-Replaced thermostat
-10 blade E-fan upgrade

Soon to have proper alignment and brakes bleed.

Will post pictures after I get back from Reno

Geez you got that all done already? Sometimes i feel like I'll never finish, oh to only work and wrench...