Not Your Average Cooling System Problem

Performance mods and Advanced Stroker discussion.
Post Reply
sandfreestyle
Posts: 4
Joined: December 1st, 2015, 2:29 pm
Vehicle Year: 1994
Vehicle Make: Jeep
Vehicle Model: XJ

Not Your Average Cooling System Problem

Post by sandfreestyle »

I’ve been trouble shooting this cooling problem for months and I just can’t figure it out. I've read countless thread on multiple forums, read repair manuals, read the FSM, laser temp check everything, still can't figure it out

Installed a new 4.7 stroker about a year ago and since then I have been having a very odd cooling system gremlin. When I first start up the car it gets to about 195-200* and it will hold there for about 5 min/miles then it will creep to 210* for another 5min/miles and then start creeping to 225*. It holds there while driving but when start/stop traffic happens it will just slowly creep up. Even with the electric fan it will only hold at that temp or very slowly creep. I can’t figure out why this is happening.

94 XJ with 4.7 stroker w/ about 1,500ish miles (mainly freeway easy driving)
New 180* t-stat
New temps sensors (t-stat housing and back of block, both reading within spec)
New high-flow water pump
New upper and lower re-enforced hoses
New aluminum 3-row radiator
16psi cap
ZJ fan clutch (working properly via drag when cold and stops spinning when shut-off hot)
97+ aux fan
60/40 coolant mix
Timing is dead on
14.5-14.8 AFR (on the smog rollers)
26lbs injectors @ 50psi (per builder’s specs)
91 octane fuel only
jsawduste
My keyboard is getting warn out
My keyboard is getting warn out
Posts: 1032
Joined: February 28th, 2008, 3:13 am
Stroker Displacement: 4.9
Location: Michigan

Re: Not Your Average Cooling System Problem

Post by jsawduste »

sandfreestyle wrote: September 17th, 2018, 2:34 pm I’ve been trouble shooting this cooling problem for months and I just can’t figure it out. I've read countless thread on multiple forums, read repair manuals, read the FSM, laser temp check everything, still can't figure it out

Installed a new 4.7 stroker about a year ago and since then I have been having a very odd cooling system gremlin. When I first start up the car it gets to about 195-200* and it will hold there for about 5 min/miles then it will creep to 210* for another 5min/miles and then start creeping to 225*. It holds there while driving but when start/stop traffic happens it will just slowly creep up. Even with the electric fan it will only hold at that temp or very slowly creep. I can’t figure out why this is happening.

94 XJ with 4.7 stroker w/ about 1,500ish miles (mainly freeway easy driving)
New 180* t-stat Should be a Factory Mopar 195.
New temps sensors (t-stat housing and back of block, both reading within spec)
New high-flow water pump Stock works just fine
New upper and lower re-enforced hoses
New aluminum 3-row radiator That's not an improvement and is most likely your biggest issue. It might be 3 rows but to fit the vehicle those 3 rows may actually have less surface area. Id also bet the fin count is such that it is more restrictive to airflow.
16psi cap
ZJ fan clutch (working properly via drag when cold and stops spinning when shut-off hot)
97+ aux fan
60/40 coolant mix
Timing is dead on
14.5-14.8 AFR (on the smog rollers)
26lbs injectors @ 50psi (per builder’s specs)
91 octane fuel only
Get a stock OEM radiator and a stock WP. The factory guys are pretty smart and they spent a lot of time designing a cooling system that works pretty good. Vast majority of aftermarket parts are a step backwards. Remember aluminum absorbs heat well but doesn't rid itself of heat so good.
User avatar
Cheromaniac
I live here
I live here
Posts: 3180
Joined: March 8th, 2008, 12:58 pm
Stroker Displacement: 4563cc
Vehicle Year: 1992
Vehicle Make: Jeep
Vehicle Model: Cherokee
Location: Cyprus
Contact:

Re: Not Your Average Cooling System Problem

Post by Cheromaniac »

I was also going to suggest that the radiator is the problem. Aftermarket radiators cram three rows instead of two into the same (or only slightly greater) thickness, resulting in the passages being smaller than stock.
A new two-row OEM radiator should alleviate the problem.
1992 XJ 4.6 I6 - 5MT - Stroker build-up, Stroker "recipes" Sold
1995 Mustang GT - 4AT - Modded Sold
2006 Mustang GT - 5MT - Modded Midlife Crisis Car :mrgreen:
sandfreestyle
Posts: 4
Joined: December 1st, 2015, 2:29 pm
Vehicle Year: 1994
Vehicle Make: Jeep
Vehicle Model: XJ

Re: Not Your Average Cooling System Problem

Post by sandfreestyle »

I had a 2-row radiator and had the same problem, but the only thing I haven't changed is the pump. I did do the restrictor in the hose (tried 1/2, 5/8, and 3/4) with no effect.

I tried "burping" the head by pulling the temp sender in the head while on a steep hill, even dropped on air in the front tires. Was at about 30* butt high when done.

Lower hose is not collapsed at all.

I'd have to get a pic of the plugs, but I've tried normal Champions, Champion Iridium, E3, colder Champions and with same results.

Tried fuel pressures at 39, 50, and 58 psi on the rail.
LRSimons
Making Progress
Making Progress
Posts: 57
Joined: September 14th, 2017, 5:52 pm
Vehicle Year: 1995
Vehicle Make: Jeep
Vehicle Model: XJ

Re: Not Your Average Cooling System Problem

Post by LRSimons »

Try the hood spacer thing. With that and wrapped header along with no ac stuff I can drive around with no fan just fine. Granted it doesn't sit in traffic or run trails but as long as it's moving it stays cool.
sandfreestyle
Posts: 4
Joined: December 1st, 2015, 2:29 pm
Vehicle Year: 1994
Vehicle Make: Jeep
Vehicle Model: XJ

Re: Not Your Average Cooling System Problem

Post by sandfreestyle »

I have a fully functional cowl induction hood
BcurpKodiak
Making Progress
Making Progress
Posts: 73
Joined: November 2nd, 2015, 8:12 pm
Vehicle Year: 1997
Vehicle Make: Jeep
Vehicle Model: XJ

Re: Not Your Average Cooling System Problem

Post by BcurpKodiak »

I don't think your T-stat is your problem. But for some reason everyone still states that you should stick to factory which is only true if you're not doing any tuning. I run a 180° high flow and am tuned for it (has to do with open/closed loop). When you open it sooner you don't only tend to have slightly lower temps but you have more tame temp swings above 200° which allowed my tuner to give it a littler more timing. Just my .02. The internet is ripe with people telling everyone to run a stock 195° which I followed at first and found through experience that generally speaking it's false.
I6FAN
I made it to triple digits!
I made it to triple digits!
Posts: 172
Joined: March 28th, 2010, 9:31 am
Stroker Displacement: 4.2
Vehicle Year: 1987
Vehicle Make: jeep
Vehicle Model: wrangler

Re: Not Your Average Cooling System Problem

Post by I6FAN »

OP, I didn't see where you mentioned you had a "standard" or "reverse" rotation water pump. That could be a problem for sure!
I6FAN
I made it to triple digits!
I made it to triple digits!
Posts: 172
Joined: March 28th, 2010, 9:31 am
Stroker Displacement: 4.2
Vehicle Year: 1987
Vehicle Make: jeep
Vehicle Model: wrangler

Re: Not Your Average Cooling System Problem

Post by I6FAN »

Oh, and same with aux fan spin direction(?).
SIXPAK
Consistent
Consistent
Posts: 217
Joined: March 8th, 2008, 5:34 am
Stroker Displacement: 280

Re: Not Your Average Cooling System Problem

Post by SIXPAK »

I6FAN wrote: September 19th, 2018, 10:55 pm OP, I didn't see where you mentioned you had a "standard" or "reverse" rotation water pump. That could be a problem for sure!
Ive seen this more than once!
Post Reply

Who is online

Users browsing this forum: Google [Bot] and 21 guests