Long winded post. I’ve read many different coolant topics on here and can’t seem to figure this out…
Before I dive into the complete cooling system overhaul detailed by Chris, wanted to see if I could pinpoint what is causing my higher temps at hwy speed.
Recently bought my 03’ rubicon with 118k miles. PO looked to be using full strength redish coolant (not rusty, just burgundy red) so over the last few days I’ve been removing coolant a gallon at a time and mixing it 50/50 with distilled water. At this point I’d say I’m close to a 60/40 split (heavy on the coolant side)
Around town only driving, per my OBD tool and my iPhone app, coolant will sit around 195-low 200s. Today when driving approx 55-70mph on the hwy coolant temps will creep up to the high 222 (as high as till 230/232 when the coolant was full strength) with 80 degree ambient temp. When getting off the hwy, coolant dropped from 222 to 217 within the distance of the exit. Then when idling for a few minutes at the end of the exit, temps went down to 210/212. Then 1-2 miles of city driving brings coolant down to mid 200’s. Then park in my garage it will idle at mid to low 200’s for however long I let it sit there(tested 10 minutes). While in the garage if I put it in neutral and rev to 2k rmps, coolant temp drops quickly to 195 then back up to low 200’s when back to idling for a few min.
Radiator appears to be mopar but doesn’t look original. No build up inside the radiator (see pictures) and no mud on the exterior of the radiator
Lower rad hose coil seems to be good so don’t think it’s collapsing at speed
New stant 18 cap
Fan clutch has same resistance when hot and cold (stuck in the engaged position?)
Thermostat appears to be working properly and appears to be 195 judging by coolant read outs
AC not on during any of this. AC will slowly raise coolant temp while at an idle
Any ideas what causing this hwy temp heat up?
Before I dive into the complete cooling system overhaul detailed by Chris, wanted to see if I could pinpoint what is causing my higher temps at hwy speed.
Recently bought my 03’ rubicon with 118k miles. PO looked to be using full strength redish coolant (not rusty, just burgundy red) so over the last few days I’ve been removing coolant a gallon at a time and mixing it 50/50 with distilled water. At this point I’d say I’m close to a 60/40 split (heavy on the coolant side)
Around town only driving, per my OBD tool and my iPhone app, coolant will sit around 195-low 200s. Today when driving approx 55-70mph on the hwy coolant temps will creep up to the high 222 (as high as till 230/232 when the coolant was full strength) with 80 degree ambient temp. When getting off the hwy, coolant dropped from 222 to 217 within the distance of the exit. Then when idling for a few minutes at the end of the exit, temps went down to 210/212. Then 1-2 miles of city driving brings coolant down to mid 200’s. Then park in my garage it will idle at mid to low 200’s for however long I let it sit there(tested 10 minutes). While in the garage if I put it in neutral and rev to 2k rmps, coolant temp drops quickly to 195 then back up to low 200’s when back to idling for a few min.
Radiator appears to be mopar but doesn’t look original. No build up inside the radiator (see pictures) and no mud on the exterior of the radiator
Lower rad hose coil seems to be good so don’t think it’s collapsing at speed
New stant 18 cap
Fan clutch has same resistance when hot and cold (stuck in the engaged position?)
Thermostat appears to be working properly and appears to be 195 judging by coolant read outs
AC not on during any of this. AC will slowly raise coolant temp while at an idle
Any ideas what causing this hwy temp heat up?
