Coolant Temp?

fiver49er

Active member
Apr 17, 2023
33
7
North Carolina
I have an '04 D2 with original 4.6. I replaced the head gaskets last fall and I want to make sure I'm keep this thing running at the right temp. What's the ideal temp range? When driving on the highway, mine will usually stay between 188 - 195F. The other day in heavy traffic, hot & humid day (90F), waiting at stop lights, it hit 210. For context, I replaced all coolant system hoses, water pump (OEM style), and thermostat last year. Thanks.
 

WaltNYC

Well-known member
Mar 3, 2010
805
204
NYC
I think you experience is pretty typical for a stock set up. A heavy duty fan clutch (I swap to HD in the summer), in-line t-stat, 180 deg t-stat, and Flowkooler water pump can all help to lower temps and allow you to keep the A/C on a bit longer.

Also, if your temps are from an OBD source, invest in an inexpensive IR thermometer to verify/calibrate temps. I've had temp sensors that were dramatically different from IR readings.
 

Howski

Well-known member
Oct 19, 2009
1,553
237
Alabama
Get the OEM Saudi market (gray in color) thermostat. Think Rovers North and others sell it. Had an in line setup on my D2 for awhile but ultimately went back to this and was pleased with results. Iirc it would usually stay below mid 190’s, occasionally may bump into low 200’s in stop/go on a hot day. Also felt the factory setup had better interior heat in the winter than in line setup
 
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fiver49er

Active member
Apr 17, 2023
33
7
North Carolina
Thanks, that's helpful. I get nervous when the temp hits 205+. I know that's fine for other cars, but based on everything I've read, over time, that seems to be pushing it with these engines if

When I replaced the thermostat last year, I did get the soft spring grey one (warm weather) from Atlantic British.

I replaced everything in the cooling system last year except the radiator. I may replace that and go back and put in a Flowkooler water pump (read good things about it). Any recommendations for a radiator?
 

mlnnc

Well-known member
Mar 23, 2008
273
35
Charlotte
The thermostat is not the problem, if there is a problem at all.

Once the thermostat opens, if it opens fully, it no longer has any role in regulating temps.

The temps you report are within spec. How are you monitoring them? UltraGauge? The auxiliary fan doesn't even kick in until 212°F. Although there are some on these forums obsessed with mods to get lower temps.
 

kris812

Well-known member
Jun 11, 2014
520
193
Tucson AZ
Totally Normal temps IMO..

However its worth checking and making sure both AC fans are spinning as well.. I put "toyota" drop in new motors on my D1 when they died and have to say they spin faster than I've ever seen in the past. I'll take any extra cooling I can get!

Also FAN clutch.. Put on a HD one and your truck will sound like a Helicopter!
 

fiver49er

Active member
Apr 17, 2023
33
7
North Carolina
Totally Normal temps IMO..

However its worth checking and making sure both AC fans are spinning as well.. I put "toyota" drop in new motors on my D1 when they died and have to say they spin faster than I've ever seen in the past. I'll take any extra cooling I can get!

Also FAN clutch.. Put on a HD one and your truck will sound like a Helicopter!
What's your take on electric fans?
 

kris812

Well-known member
Jun 11, 2014
520
193
Tucson AZ
I like the 2 ac electric fans and 1 mechanical fan.. Fail safe..

However, my brother installed electric fans and a controller in his Nissan race car. Definitely able to get cooler.

But now you have a controller and extra wires that could fail.. And reliance on having power to have cooling.

So 50/50, better cooling but 'probably' not as reliable long term.. I mean in the feild I can Lock up a fan clutch with wire and make it cool; once an electric fan died, it's dead..
 
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fiver49er

Active member
Apr 17, 2023
33
7
North Carolina
I like the 2 ac electric fans and 1 mechanical fan.. Fail safe..

However, my brother installed electric fans and a controller in his Nissan race car. Definitely able to get cooler.

But now you have a controller and extra wires that could fail.. And reliance on having power to have cooling.

So 50/50, better cooling but 'probably' not as reliable long term.. I mean in the feild I can Lock up a fan clutch with wire and make it cool; once an electric fan died, it's dead..
Makes sense. Thanks.
 

4Runner

Well-known member
May 24, 2007
722
140
Boise Idaho
I like the 2 ac electric fans and 1 mechanical fan.. Fail safe..

However, my brother installed electric fans and a controller in his Nissan race car. Definitely able to get cooler.

But now you have a controller and extra wires that could fail.. And reliance on having power to have cooling.

So 50/50, better cooling but 'probably' not as reliable long term.. I mean in the feild I can Lock up a fan clutch with wire and make it cool; once an electric fan died, it's dead..
If we were all worried about an extra controller, wires, and power than no one would go off-roading in any Rover newer than 95. 🤪
 
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kris812

Well-known member
Jun 11, 2014
520
193
Tucson AZ
LOL I've sunk my rover in DEEP before.. Only thing that stopped me was a crack in the gas fill vent tube.. AND there she stayed for an hour.. Then flushed tank on site and tossed 5 gallon into her..

AND THEN, Trans was full of water and killed it 2k miles later, even though I flushed the piss out of it... Trans guy said 1/2 cup of water, and auto trans clutch plates fall apart.. It took on an easy gallon+ into trans soo the fact I made it home impressed me..

PSA check your vent tubes on trans/t case and diffs... Mine were melted near the exhaust, RIP my wallet..
 
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