WEIRD 2004 DISCO

boulder4x4

Active member
Callsign: 2X4
Sep 17, 2017
36
0
Colorado
Why does my 04 discovery cool down (176) when I slow down and get warmer when there is a load on the engine... yes there is air in the heater core and I have done the in-line thermostat mod. the engine stays cool and does not get above 204 but that is still too high for me.


so....


what is the best way to get the air out of the heater core and why does it cool down on the slow down.
 

Howski

Well-known member
Oct 19, 2009
914
2
Greenville, S.C.
Swap the heater core lines if you’ve tried conventional methods. I typically run without the cap off for a long trip and it usually works the air out. If there are any ‘small’ air pockets left they usually work themselves out in a day or two (with cap on)
 

coop74

Well-known member
Dec 10, 2015
253
1
Alcoa TN
for about 60 bucks you can buy a kit that will pull a vacuum on the cooling system and then fill it up with out any air bubbles. I fought burping it the regular way many times and then finally broke down and bought the tool. Well worth it.
 

CORover

Well-known member
Jun 11, 2007
408
6
Colorado, USA
for about 60 bucks you can buy a kit that will pull a vacuum on the cooling system and then fill it up with out any air bubbles. I fought burping it the regular way many times and then finally broke down and bought the tool. Well worth it.

Which one did you buy?
 

JohnB

Well-known member
Oct 18, 2007
2,219
0
Oregon
I would assume your fan clutch isn't doing its job. If you can coast down a hill with no load and the temps drop can only assume your clutch is not grabbing well when you are working the engine.
 

boulder4x4

Active member
Callsign: 2X4
Sep 17, 2017
36
0
Colorado
that's true... but it does have the consistency of peanut butter when you spin it. I finally got the air out. but I cant really leave well enough alone. now I have air in it again.
 

proper4wd

Well-known member
Jun 11, 2015
59
0
boston
let's re visit this. you are surprised that your engine generates more heat when under load?

204 is perfectly acceptable and about 20 degrees cooler than they typically run with all factory parts. youre chasing a ghost.
 

Agent

Well-known member
Jun 20, 2007
664
0
WV
let's re visit this. you are surprised that your engine generates more heat when under load?

204 is perfectly acceptable and about 20 degrees cooler than they typically run with all factory parts. youre chasing a ghost.
I agree. Unless you're running a 180 thermostat temps north of 200 degrees is normal.
 

boulder4x4

Active member
Callsign: 2X4
Sep 17, 2017
36
0
Colorado
See...I knew it... I am running a 180 thermostat, I knew it should not get to 204..... But, I chased all the air out with a broom and told it to never come back. And it runs fine now. Went to the mountains and did a trail and it never reached 200. :applause:


thank you all for your help.

ps: I have a full CDL kit from an 04 any takers?
 

JUKE179r

Well-known member
Sep 14, 2016
198
1
Suffolk, England
I have this one but I couldn't pull as much vacuum as I needed for the disco. it would hold the vacuum but not pull any more.






https://vergedeal.com/products/auto-cooling-system-vacuum-purge-and-refill-kit
I've got a kit just like that one.
The problem I found is that you have to plug/cap off the coolant reservoir overflow tube. That's where it sucks air from and I couldn't get a good vacuum pull to bleed the coolant system. After I corrected that issue it worked great.
 

MacRoadie

Well-known member
Jan 24, 2017
111
0
Placentia, CA
I agree. Unless you're running a 180 thermostat temps north of 200 degrees is normal.
What has that got to do with anything?

The temperature rating of a thermostat simply indicates at what temperature it is going to start to open at. The stat will typically be fully open about 20 degrees above that number.

The number has zero to do with how hot the engine will eventually get, or its normal operating temperature. Open is open, and closed is closed. Eliminate the stat entirely, and the engine is still going to get to its normal operating temperature, maybe a bit slower in cold weather, but its going to get there no matter what.
 

jastutte

Well-known member
Nov 10, 2009
202
0
What has that got to do with anything?

The temperature rating of a thermostat simply indicates at what temperature it is going to start to open at. The stat will typically be fully open about 20 degrees above that number.

The number has zero to do with how hot the engine will eventually get, or its normal operating temperature. Open is open, and closed is closed. Eliminate the stat entirely, and the engine is still going to get to its normal operating temperature, maybe a bit slower in cold weather, but its going to get there no matter what.
i have read this a few times in a few different places and it makes sense. but it is not my experience. all three of my rovers run cooler with the 180 degree thermostat. we do all kinds of driving in them. city with and with out the A/C and highway with and with out the A/C. the coolant temps as monitored by a UG and an app are consistently lower than when i ran the 190 degree thermostat.
 

K-rover

Well-known member
Jan 15, 2010
1,874
1
Raleigh, NC
i have read this a few times in a few different places and it makes sense. but it is not my experience. all three of my rovers run cooler with the 180 degree thermostat. we do all kinds of driving in them. city with and with out the A/C and highway with and with out the A/C. the coolant temps as monitored by a UG and an app are consistently lower than when i ran the 190 degree thermostat.



Yep, My D2 used to get to 215-220 with the stock Tstat. with just doing the 180 swap I only get to 201 at idle and it goes down to 188 highway and around 194 driving around town.. Never saw those temps with the stock Tstat
 

MacRoadie

Well-known member
Jan 24, 2017
111
0
Placentia, CA
i have read this a few times in a few different places and it makes sense. but it is not my experience. all three of my rovers run cooler with the 180 degree thermostat. we do all kinds of driving in them. city with and with out the A/C and highway with and with out the A/C. the coolant temps as monitored by a UG and an app are consistently lower than when i ran the 190 degree thermostat.
I would place more weight on the possibility that the aftermarket body and disk open more fully (i.e. are less restrictive) than the stock unit. At 195 degrees, a 180 degree t-stat is fully open, and a 190 degree t-stat is fully open at 205. Above 205 degrees, both units are fully open and allowing 100% coolant flow. The only restriction would be the mechanical design and flow capacity of the body and disk, and the travel allowed by the heat motor and spring. That scenario is quite possible and logical.

At the end of the day, if you live in a warm climate, you could ostensibly remove the t-stat completely and have unrestricted coolant flow. Even then, if the engine wants to run at 210-215 degrees, that's where it's going to run.

ETA: As an aside, I own a C7 Z06 Corvette, and one of the huge debates that rages on and on in the Vette forums, is the use of 160 degree t-stats. Do you need one? Do you need to alter the tune to use one? What happens in cold weather (cars like to throw codes if the ECU reads too much throttle/boost before the car reaches OEM tune operating temperature)? Which one to use?

Turns out lots of guys were using a Mishimoto aftermarket 160 degree stat and not seeing any difference whatsoever, while guys using other brands WERE seeing significant differences. Turns out, the Mishimoto utilizes a rubber ring gasket that both seals the unit to the housing that wasn't integrated into the t-stat, and was significantly larger. The gasket was actually restricting coolant flow, so even though the unit was opening earlier, it was allowing less coolant flow and negating the benefit:


Mishimoto on left, Racecraft on right.

I understand these are drop-in units, versus the integrated t-stats in a Disco, but the principle of flow restriction would still apply.

Now, if you're TRYING to run the engine at a temperature lower than design temp, that's a different story. Land Rover purposely installed 88C t-stats in these trucks because they wanted them to run in the 200-205 degree range (for a host of reasons). You certainly can get the coolant temp down consistently if you run a colder stat,
 
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