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Discussion Starter · #1 ·
04 135k mi
Head gaskets done not too long ago.
New tstat at that time.
New radiator about 2 years ago.

Running at about 204 after driving/idling.
Drops to about 197 when rolling down the road.

Am I flirting with trouble?
What would be my steps 1, 2, 3 to start getting that temp down?

Everything seems to be in good working order - just seems a little hi on the temp readings and in Arizona it's only gonna get hotter.
 

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Haven't seen you here in a bit. Good to know you're still kicking around.

Try these, in this order. One at a time. Except the last one.

What thermostat did you use? I'd suggest the low-temp unit. It's MotoRad part #439-180 . It will give you some headroom at idle with poor airflow, like sitting stopped on hot asphalt on a bad day, or under a heavier load. It just gives you an extra few degrees of temp climb before getting to boil over. I have read that they flow a little better but I don't know if that's true. Some sort of internal spring loaded bypass. Not sure on that.

All radiators are not alike. If you bought a cheap one, or just ended up with one and over-paid, It won't perform like a good one. The Nissens is a very good replacement and under $200. The others are all pretty much Chinese. maybe you have a local radiator shop that can flow test it. I've seen under the tanks on some of those cheap imports and it looks like they have monkeys soldering the cores to the ends. No wonder they don't flow.

You might try a water pump replacement. Use only a premium aftermarket with the metal impeller. Delco Pro is $65 on Rockauto. Impellers can deteriorate due to the effects of cavitation and will eventually reduce coolant flow.

If you're still getting warm, an auxiliary oil cooler will definitely help. Right now, the system is relying on conduction internally to cool the oil. This places a load on the primary cooling system. Running the oil through a separate system relieves a big burden from the radiator, freeing it up to carry more load.

Also, check your aux electric fan. They are a high failure rate item. It should kick on at startup for a moment and any time the AC is switched to max.
 

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Hey!!!! Have not seen your name in a while ... Welcome back?
It's a little warmer than preferred in my opinion but not terrible.
From your description it gets better at speed (speed means to me more airflow through the rad) maybe have a look at the fan clutch? Did you replace the water pump last year?
 

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Hey!!!! Have not seen your name in a while ... Welcome back?
It's a little warmer than preferred in my opinion but not terrible.
From your description it gets better at speed (speed means to me more airflow through the rad) maybe have a look at the fan clutch? Did you replace the water pump last year?
Yeah- forgot the fan clutch (how could I?!)

197 isn't out of line. If it has a 192 stat in it, it's going to work within a few degrees of variation. And if the temp read is off of the OBD, you'll also get a couple degrees of variation from true reading there. One of the biggest problems is the Rover grille. It looks cool but blocks alot of airflow.
 

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Discussion Starter · #5 ·
Hey guys. I have been hanging out - just watching the forum but not posting as there are a lot more experienced folks out there.

Anyway,...
Used the 180 degree tstat.
Replaced water pump about two years ago (pre head gasket).
I think I got the radiator from Atlantic British.
Have an oil cooler already.
Aux Fans are perma-on with the AC on.
Viscous clutch "feels" good - lots of resistance when turning by hand - but, no, I didn't replace it last year.
 

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Are you absolutely certain you have the 180 stat? At no load idle with good air movement you should be right around that temp. The engine really isn't creating alot of heat in that state and shouldn't be over-taxing the cooling system. Try letting it idle and see where the heat settles at while idling. Then raise the RPM up to about 2K. If you get a temp drop, you probably have an eroded impeller. If not, it's probably the stat. How are you measuring the temps?

I remembered this thread and I bookmarked it. It's a discussion about the Motorad and the Rover 180 stat. There are comments from users consistent with the results you are seeing. Buy the genuine grey land rover 180 thermostat - Land Rover Forums - Land Rover Enthusiast Forum

Internal temperatures are much less concerning than overheats. Your engine will operate just fine at 220 degrees. Not optimally, but it'll run just fine and for a very long time. If you have a 50/50 blend, your boiling point will be at about 225. A degree under boiling and your system operates. At boiling, it stops. So obviously you want to stay as far away as you can.

How is your oil cooler set up? Where is it getting oil from and how is it returning it?
 

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Discussion Starter · #9 ·
I am using an obd port tool.
Oil cooler is stock.

It is so random.
But definitely seems hotter while driving, as opposed to idling.

Sounds like I need to keep an eye on it and either replace the clutch or radiator or both if I reach temps beyond my tolerance.
 

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That's the trans cooler.

Pull the stat and put it in a pan. Put heat to it. You can get a very accurate digital thermometer at Walmart for $10. Find out for sure where the unit is opening. If you see it opens at 195, you found your problem. Before all this, use that fancy new thermometer on the truck to confirm what the OBD is showing.

Temp will go up when driving. The engine is creating more heat. You're getting past where the radiator can effectively remove heat if the temp climbs too much.

Here's an experiment- drain the cooling system. Do it a few times to get as much out as you can- drain and fill. Or pull the block plugs. Fill with straight water, preferably distilled. If temps come down over what it was doing with AF, you probably have radiator blockage. Straight water is more thermodynamically efficient, but has a lower boiling point. In range, it will take more heat out of the system. But if you get a really hot day and you're under a heavy load and it hits 212, you're done.
 

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04 135k mi
Head gaskets done not too long ago.
New tstat at that time.
New radiator about 2 years ago.

Running at about 204 after driving/idling.
Drops to about 197 when rolling down the road.

Am I flirting with trouble?
What would be my steps 1, 2, 3 to start getting that temp down?

Everything seems to be in good working order - just seems a little hi on the temp readings and in Arizona it's only gonna get hotter.
Where are you located. Sounds like a warm climate if you have the air-con on all the time. None of those figures are a concern if you are in a warmer climate.
The thermostat temp is the temp that it starts to open. That is it will only open a very small amount at that temp. It will generally take another 10 degrees for it to fully open.
 

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Here's an experiment- drain the cooling system. Do it a few times to get as much out as you can- drain and fill. Or pull the block plugs. Fill with straight water, preferably distilled. If temps come down over what it was doing with AF, you probably have radiator blockage. Straight water is more thermodynamically efficient, but has a lower boiling point. In range, it will take more heat out of the system. But if you get a really hot day and you're under a heavy load and it hits 212, you're done.
Two experiments in the one post. I could comment, but I won't.
As water does not retain the heat like glycol coolant, it will not get as hot as a glycol coolant. Yes, Glycol has a higher boiling point than water, but it needs this higher point as it will retain more heat. Most people will find a 5 to 10F drop in running temps when switch away from glycol coolant. By highlighting its only advantage, you are also highlighting its major disadvantage.
 

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Ian- How about not taking a giant, steaming **** on this thread and keep away from theoretical discussions and your various re-engineering theories. He just needs to walk through some basic diagnostic steps.
I was just commenting on the world according to CT090 when you were warning the guy about running water in the cooling system. I did not want him to get worried.
Your suggestion was a good one for a change. That is, run straight water and see if it improves his temps. If it does, and he does not live in a climate that gets below freezing, then he should dump the glycol based coolant and use a water based one.
Straight water is more thermodynamically efficient, but has a lower boiling point. In range, it will take more heat out of the system.
 

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...and back to our regular broadcast...

Would higher temp at speed / lower temp at idle suggests radiator blockage, as opposed to viscous clutch. ?

My gut says radiator..
Can I get an amen?
Not really. At higher speeds your motor is working harder and therefore getting hotter. On a 100F day my car will run hotter at 60mph than what it does at 50mph.
You are going through what I did last year. My running temps were in line with yours. They are not bad, I just wanted it to run a bit cooler. Tried most things with little difference. It was only changing from a glycol based coolant to a non-glycol one that made any noticeable difference. Your temps are not bad, it is just they could probably be better.
You have not answered in regard to what climate you live in. The climate has a significant impact on whether your temps are normal or not.
Do you have anything sitting in front of the grill, like driving lights, bullbar, etc. Have you replaced the front skirts with a bullbar or something.
What motor do you have, a 4.6 generates more heat than a 4.0.
There are so many little things that can cause a few degrees in operating temperature and I have gone through the lot. I keep on coming back to that there is nothing obviously wrong with your temps. Maybe your radiator is a little blocked, but there are many other things that could be a problem as well.
 

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...and back to our regular broadcast...

Would higher temp at speed / lower temp at idle suggests radiator blockage, as opposed to viscous clutch. ?

My gut says radiator..
Can I get an amen?
Once you're moving more than about 25 the fan clutch disengages.

You need to find out if you're dealing with real temps by determining them another way- a reliable measurement. Then you need to look at the device that regulates the temps- the tstat.
 
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