Flushed coolant, still a click above 210?

[ehall]

Are you sure you bought a relief cap? They aren't all relief caps

 

[jordan96xj]

erykv1,

I can't see from the dash pics, but do you have a tachometer? (or an obd2 scanner that will give you RPM) Could you tell us what RPM you have at 60mph? What is your typical cruising speed? Can you give the RPM for that as well?

(If for any reason your RPMs are high for that speed, that will also drive the coolant temperature up. Mine sticks at 210, but if run hard for a bit (2500+ rpm) I can definitely get it to climb. And it comes back down to 210 pretty quickly when I back off).

 

[Ecomike]

Thank you for this Ecomike!

Is there some allowable delta in temperature difference between the upper and lower radiator hose that indicates the radiator is not doing its job?

Great question, I was once thought that the larger the delta T, temperature drop across the radiator the better the cooling system was working, but then one day I notice the drop was about 45 degrees with the old blocked raidator and only a 10 degree drop with the new radiator that solved my cooling problems. The difference was flow rate of coolant through the radiator. Higher flow rate less Delta T, but more net cooling.

Just an example compare 1/2 GPM at a delta T of 40 degrees to 5 GPM and a delta T of 10 degrees F.

1/2 X 40 = 20

5 x 10 = 50

With out knowing, measuring, the flow rate there is no way to access the actual cooling rate with just the delta T.

 

[erykv1]

Your ambient temperature shouldn't have a drastic effect on your coolant temperature.

It means that your cooling system isn't doing its job effectively. Especially at 80 degrees outside.

I agree. Now to find out what it is..

Are you sure you bought a relief cap? They aren't all relief caps

I bought a Stant 10231 Radiator Cap, listed at a 16psi relief.

erykv1,

I can't see from the dash pics, but do you have a tachometer? (or an obd2 scanner that will give you RPM) Could you tell us what RPM you have at 60mph? What is your typical cruising speed? Can you give the RPM for that as well?

(If for any reason your RPMs are high for that speed, that will also drive the coolant temperature up. Mine sticks at 210, but if run hard for a bit (2500+ rpm) I can definitely get it to climb. And it comes back down to 210 pretty quickly when I back off).

I dont know off the top of my head, but I'm on 33's on factory 3.55 lol. Its a pig.

Great question, I was once thought that the larger the delta T, temperature drop across the radiator the better the cooling system was working, but then one day I notice the drop was about 45 degrees with the old blocked raidator and only a 10 degree drop with the new radiator that solved my cooling problems. The difference was flow rate of coolant through the radiator. Higher flow rate less Delta T, but more net cooling.

Just an example compare 1/2 GPM at a delta T of 40 degrees to 5 GPM and a delta T of 10 degrees F.

1/2 X 40 = 20

5 x 10 = 50

With out knowing, measuring, the flow rate there is no way to access the actual cooling rate with just the delta T.

Sounds like I may have gunked up this radiator then. I may go ahead and replace the t-stat first. If it still doesnt fix it, I will order another radiator. Good thing parts arent terribly expensive for the XJ's!

 

[Transpoquick]

The 33's and 3.55's are a problem.
How many miles on that engine?
Trying to make that combo run @ 210 will prob not work.
180 t-stat, electric fan w/ a adjustable temp. would help.

 

[md21722]

I'm having difficulty that a 4 month old radiator would already be trash.

If a new dealer thermostat & radiator cap don't solve the problem I'd look to see if you are leaking coolant/ bad head gasket/ gear ratio.

Where on "earth" are you... what region at least?

 

[erykv1]

The 33's and 3.55's are a problem.
How many miles on that engine?
Trying to make that combo run @ 210 will prob not work.
180 t-stat, electric fan w/ a adjustable temp. would help.

The engine was supposedly rebuilt when I bought it, so I'd say ~30k. But I have my doubts. There is 156k on the ODO right now. I've had zero issues with it keeping 210 last summer and nothing has changed.

I'm having difficulty that a 4 month old radiator would already be trash.

If a new dealer thermostat & radiator cap don't solve the problem I'd look to see if you are leaking coolant/ bad head gasket/ gear ratio.

Where on "earth" are you... what region at least?

I'm located in GA.

Coolant bottle seems to be at the same level / no signs of coolant loss. I do have an 01 XJ, and the 0331 head cracking is always at the back of my mind. I have never let it overheat to the red. As soon as it gets past 1 click I've always shut it off and let cool. The oil looks fine, not frothy or milky at all. If my head was cracked I would be loosing coolant right?

I should mention, when I did the coolant flush. There was a lot of brown muck / stuff in the coolant overflow. I assume leftover from not flushing the system completely the first time I replaced all the cooling components.

I'll replace the cheap stuff first and go from there.

 

[RedHeep]

The 33's and 3.55's are a problem.
How many miles on that engine?
Trying to make that combo run @ 210 will prob not work.
180 t-stat, electric fan w/ a adjustable temp. would help.

Everything you just suggested is exactly the opposite of what experienced XJ owners know and will tell you.

Electric fans don't work. They're a hassle and they don't flow enough air.

The 4.0 is designed to run at 195, that's why it has a 195 thermostat in it. Opening the thermostat early at 180 degrees does not increase the effectiveness of the cooling system, particularly the radiator. All it does is allow the coolant to go into the radiator 2 minutes before it normally would with the right thermostat in it.

There are a ton of people running around on 33's with stock gears. I did it for 2 years with no issues on my '91.

If I can run on 37's with 5.38 gears at 2500 rpm at 60 mph on the highway and never get the needle to move over 195, a much smaller XJ should have no issues doing the same.

OP, you're wasting your time changing your thermostat. If it wasn't working, the needle would be 260 and you'd be on the side of the road. You either got a junk radiator or something happened to screw it up after the fact.

A 100 bucks at the local parts store and 30 minutes with a 10mm socket will fix your problem.

 

[erykv1]

Everything you just suggested is exactly the opposite of what experienced XJ owners know and will tell you.

Electric fans don't work. They're a hassle and they don't flow enough air.

The 4.0 is designed to run at 195, that's why it has a 195 thermostat in it. Opening the thermostat early at 180 degrees does not increase the effectiveness of the cooling system, particularly the radiator. All it does is allow the coolant to go into the radiator 2 minutes before it normally would with the right thermostat in it.

There are a ton of people running around on 33's with stock gears. I did it for 2 years with no issues on my '91.

If I can run on 37's with 5.38 gears at 2500 rpm at 60 mph on the highway and never get the needle to move over 195, a much smaller XJ should have no issues doing the same.

OP, you're wasting your time changing your thermostat. If it wasn't working, the needle would be 260 and you'd be on the side of the road. You either got a junk radiator or something happened to screw it up after the fact.

A 100 bucks at the local parts store and 30 minutes with a 10mm socket will fix your problem.

Your $100 bucks was in reference to a radiator right?

 

[erykv1]

Also, before I pull the trigger on another spectra unit... a quick eBay search has yielded some all aluminum 3 row radiators for $99... too good to be true?

 

[Digger87xj]

Too good to be true. they are junk.

 

[dan1977p]

The Murray I got from O'Reillys has worked great for me. Different option if the Spectra isn't up to the OE spec.

 

[md21722]

OP, you're wasting your time changing your thermostat. If it wasn't working, the needle would be 260 and you'd be on the side of the road. You either got a junk radiator or something happened to screw it up after the fact.

I have had thermostats fail to open completely so that temperature would only go up a bit under load.
I've also had thermostats that failed totally and caused 260F and pull over..

Is the heater core bypass a loop of hose or is it capped at both ends?

 

[erykv1]

Too good to be true. they are junk.

Figured as much, thanks for the input!

The Murray I got from O'Reillys has worked great for me. Different option if the Spectra isn't up to the OE spec.

I have had thermostats fail to open completely so that temperature would only go up a bit under load.
I've also had thermostats that failed totally and caused 260F and pull over..

Is the heater core bypass a loop of hose or is it capped at both ends?

My heatercore bypass is currently looped. After some searching it seems like the OEM Mopar unit has the best reviews, but it comes in quite hefty at $260~

I may suck it up and get the Mopar unit or a champion 2 row. I don't want to keep buying Spectras, lol.

 

[md21722]

I haven't had any warm running with my Spectras but I don't run 33" tires either.

Consider that you are pumping unrestricted hot coolant out of the head straight into the block with a loop. I don't know what the flow rate through the heater core is, or is effective heat transfer when the fan isn't blowing air through it. But it would be cheap & easy to cut the loop and cap both ends.

 

[Ecomike]

I have had thermostats fail to open completely so that temperature would only go up a bit under load.
I've also had thermostats that failed totally and caused 260F and pull over..

Is the heater core bypass a loop of hose or is it capped at both ends?

Good question, and I agree, T-stats can fail wide open, closed or partly open, all have different results. I found the Murray T-stats made in Israel to be the best recently.

 

[Ecomike]

I haven't had any warm running with my Spectras but I don't run 33" tires either.

Consider that you are pumping unrestricted hot coolant out of the head straight into the block with a loop. I don't know what the flow rate through the heater core is, or is effective heat transfer when the fan isn't blowing air through it. But it would be cheap & easy to cut the loop and cap both ends.

I agree, great suggestion. The heater core has a resistance to flow that a loop does not. More flow will go through the radiator with out the loop.


OP, be sure to do the descaling process I suggested first, then BACK-FLUSH, reverse flow the radiator and try it again. Then if that does not work, drop a new radiator in after you are 100% sure the crap in the block is all out. Also run a head gasket leak test to test for traces of CO2 combustion gases in the coolant before you risk money on another radiator as combustion gases react with coolant to scale up radiators. It can happen fast.

 

[Transpoquick]

Everything you just suggested is exactly the opposite of what experienced XJ owners know and will tell you.

Electric fans don't work. They're a hassle and they don't flow enough air.

The 4.0 is designed to run at 195, that's why it has a 195 thermostat in it. Opening the thermostat early at 180 degrees does not increase the effectiveness of the cooling system, particularly the radiator. All it does is allow the coolant to go into the radiator 2 minutes before it normally would with the right thermostat in it.

There are a ton of people running around on 33's with stock gears. I did it for 2 years with no issues on my '91.

If I can run on 37's with 5.38 gears at 2500 rpm at 60 mph on the highway and never get the needle to move over 195, a much smaller XJ should have no issues doing the same.

OP, you're wasting your time changing your thermostat. If it wasn't working, the needle would be 260 and you'd be on the side of the road. You either got a junk radiator or something happened to screw it up after the fact.

A 100 bucks at the local parts store and 30 minutes with a 10mm socket will fix your problem.

Say's u:yap:
I paid a 150.oo for my spectra, I got ripped off.
Guess that's because I don't know anything about jeeps
Don't want to make naxja member 1499 mad though.
Bwah, electric fans don't work, that's funny.

 

[Transpoquick]

Thermostat opening earlier thing is kinda "thin" too.
I guess all those people out there that bought diagnostic tuners to turn there fans on sooner in their "vehicles" and install 160 thermostats even, don't know what there doing.
Built to run at 195, Bwah.
This is like a "what kind of oil should I run post"

 

[erykv1]

I haven't had any warm running with my Spectras but I don't run 33" tires either.

Consider that you are pumping unrestricted hot coolant out of the head straight into the block with a loop. I don't know what the flow rate through the heater core is, or is effective heat transfer when the fan isn't blowing air through it. But it would be cheap & easy to cut the loop and cap both ends.

I was under the impression that the system had to be looped by the heater core as blocking it off would cause problems on an 01?

I agree, great suggestion. The heater core has a resistance to flow that a loop does not. More flow will go through the radiator with out the loop.


OP, be sure to do the descaling process I suggested first, then BACK-FLUSH, reverse flow the radiator and try it again. Then if that does not work, drop a new radiator in after you are 100% sure the crap in the block is all out. Also run a head gasket leak test to test for traces of CO2 combustion gases in the coolant before you risk money on another radiator as combustion gases react with coolant to scale up radiators. It can happen fast.

http://www.autozone.com/loan-a-tools/block-tester/oem-block-tester/391378_0_0/

Is this the block tester you are referring to? Seems like I can rent one locally at an Autozone.

Thank you all for the input.