04 D2 Running hot under load

3ac3

Active member
Apr 19, 2009
41
0
oceanside
UPDATE (weak cylinder): 04 D2 Running hot under load

Hoping Dweb team can help provide some logical next steps to fix this issue. Planning a short trip to Baja during labor day weekend and hoping to get this problem rectified.

History and equipment:
2004 D2
Owned the truck since 2008.
Lifted with 33's, armor, winch, lights, etc
Never boiled over.
Only "overheated" once (recently). First time stock guage moved above center
Scanguage to monitor

About 4 months ago I replaced the fan/clutch, radiator (nissens), and T-stat (180* OEM). System was also flushed. Also stopped using Dex and now using Peak global lifetime. Why did I replace everything? The engine was running hotter than I wanted especially on long trips through the desert. Although it never got above 235* even at 100* outside and driving up a hill/mountain with AC on. And always cooled down. Normal temps were in the 198-208* for everyday driving.

Since I've replaced the parts the truck is running around 198 - 204 around town with AC on but when it's under load it consistently get's hot (freeway speeds, mountain, even some longer hills around town) and it will climb to 220* quickly and higher. But always cools back down and motor can idle and stat at 200*

A recent trip to Big Bear saw my first "over heating". Before climbing the mountain the engine got to 245* and stock gauge moved to 3/4. I quickly pulled over and let it cool down. It was 100* outside and AC was on. After letting it cool down I continued but with AC off then started to head up the mountain grade. It jumped to 240* and I pulled off again to let it cool. I removed the grill (a little more airflow) to try one last time and made it up the mountain going very slow. Wheeled that day and never got above 215*

What seems to be working:
Fan and clutch
Radiator (20* difference between in and out hoses). LR shop also placed cardboard to block airflow and engine temps climbed but as soon as the board is removed the motor cools down quickly.
T-stat (but maybe it's sticking?)
Block test was done by my LR shop and came back good.
System bled and I don't believe to have any air
New expansion tank cap
New waterpump (replaced 2 weeks ago)
Electric condensor fan is working
Temp sensor is new and IR therm confirmed working properly

What are the logical next steps?
LR shop wants to install a second electric fan, oil cooler, etc. But I feel like that isn't addressing the issue.
If the block test came back fine that should mean the head gaskets and any other more serious internal issues like cracked block or liner are good right?

I'm thinking of having the cats checked to make sure flow is good. Only code I get is P0327 (knock sensor) which I've had for a long time on and off.

What's next? Thanks for the help.
 
Last edited:

robertf

Well-known member
Jan 22, 2006
4,781
356
-
Only code I get is P0327 (knock sensor) which I've had for a long time on and off.

Fix this. Your ignition timing is retarding. That increases cylinder temperatures
 

squirt

Well-known member
Nov 13, 2008
824
13
Los Angeles
If you're hitting 220deg+ with any regularity, you're right that there's still something wonky. On the same grade up to Big Bear where you were topping 245deg, I never get higher than ~225 during the hottest summer days. That's with a similar setup truck, A/C on, fully loaded down with family/cargo/bikes/etc. Oh, and I'm running basically original 150k mile cooling setup with cheap-o walmart green coolant. Granted, I'm not trying to set any land speed records.

Before you replace that knock sensor, look at your timing maps. It's a good thought, but it may not be having any real impact.

If the temp drop across your radiator is consistently in the 20deg range, that's pretty good for an OE-style radiator. It tells me that your engine is probably just creating too much heat for the cooling system to overcome, which could have many causes. What do your long term fuel trims look like?
 

3ac3

Active member
Apr 19, 2009
41
0
oceanside
If you're hitting 220deg+ with any regularity, you're right that there's still something wonky. On the same grade up to Big Bear where you were topping 245deg, I never get higher than ~225 during the hottest summer days. That's with a similar setup truck, A/C on, fully loaded down with family/cargo/bikes/etc. Oh, and I'm running basically original 150k mile cooling setup with cheap-o walmart green coolant. Granted, I'm not trying to set any land speed records.

Before you replace that knock sensor, look at your timing maps. It's a good thought, but it may not be having any real impact.

If the temp drop across your radiator is consistently in the 20deg range, that's pretty good for an OE-style radiator. It tells me that your engine is probably just creating too much heat for the cooling system to overcome, which could have many causes. What do your long term fuel trims look like?

Thanks. Are you asking long term fuel mpg? I get around 11mpg but honestly never pay attention as I expect it to be bad.
 

squirt

Well-known member
Nov 13, 2008
824
13
Los Angeles
Thanks. Are you asking long term fuel mpg? I get around 11mpg but honestly never pay attention as I expect it to be bad.

Not mpg... You can look at long term fuel trim (LTFT) numbers from the ECU. (I use Torque app, may be able to use scangauge..never had one) High positive numbers means it's compensating for something by adding excess fuel. High negative numbers mean it's purpoaely holding back fuel for some reason to lean out the mix. Anywhere in the +/-3% range is pretty normal.
 

Dave03S

Well-known member
Jun 22, 2012
62
2
Seattle, Wa
I would open the bleed screw first thing in the morning, dead cold engine, and see first hand if there is an air bubble in there. top it off through the bleed hole if so.

Any air in the system should wind up behind the bleed screw thus an easy place to see and eliminate.
 

special ed

Well-known member
Apr 11, 2012
182
115
Elsinore
Check your inlet and outlet temps from the heater core and see if it is blocked (air pocket trapped in there) will cause engine temps to be fine at normal driving and spike when on freeway under load.

Try bypassing the heater core and drive it!

Ran into this last year on a disco and it sent me spinning for a while till i found it.

Worst case bring it out and ill look at it for you.

Ed@IERovers.com
 

JohnB

Well-known member
Oct 18, 2007
2,292
12
Oregon
What type of intake leaks are you referring to?

Any intake leak post Air Mass Meter can make your engine run lean and hot. Might try a smoke test.
Pull the engine fan off light a cigar and blow smoke around the intake area. If the smoke is drawn in than you have a leak. Injector seals are very common and if you have over 100K they usually need replacement.
 

3ac3

Active member
Apr 19, 2009
41
0
oceanside
UPDATE (weak cylinder): 04 D2 Running hot under load

Update on the truck... Just before the Labor Day trip to the Southern Sierras I thought the problem had been solved. However the truck ran warm the entire drive from Carlsbad to the southern sierras and back home. Actually had to pull over twice to let the motor cool down after reaching 245*. This happens largely under load and at higher speeds and driving on mountain roads.

Since then I had a different rover shop take a stab at diagnosing the problem. As a reminder I've literally replaced every cooling component on the vehicle.

The shop did the following tests but we're unable to recreate the overheating. But I'm not surprised by that.
-- T4 diagnostic showed p0327 (knock sensor) which I knew about and have had for several years on and off. All other diagnostics came back fine and during a 40 mile drive test they mentioned that power felt great and ran smooth.
-- Hydrocarbon sniff test: start-up idle: 6ppm after test drive at idle: 18ppm. So despite the liquid block test coming back negative the sniff test found carbon in the cooling system
-- Cylinder compression test (dry and wet): 1=180/185 | 2=160/165 | 3=165/180 | 4=180/180 | 5=180/180 | 6=185/180 | 7=120/150 | 8=185/185
-- O2 sensors found to be working well

At this point I'm trying to decide what to do... The shop suspects weak cylinder #7 (possible #2) and/or possible Head gasket, valve, or piston/ring or liner fault. They believe this is the cause for the overheating.. They advised that the next step is to pull the heads to verify internal failure and also pressure test the block. They quoted around 8-10 hrs for tear down and inspection.

This truck had a new short block (done under warranty by LR) in 2009 and only has 50k miles on it.

I do a lot of my own work but not sure I'm qualified to verify liner failure and have all the necessary tools for this job... So if I let a shop take this on I'm already $1,500 in on the tear down just to verify failure and obviously worst case is having to re-sleeve the block.

What would the next step be from the experts? Thanks in advance..
 

jymmiejamz

Well-known member
Dec 5, 2004
6,008
361
35
Los Angeles, Ca
The chances of the shop seeing anything seriously wrong are highly unlikely. I've seen Discos where the liner is visually sticking above the block deck surface, but the vehicle had no symptoms. I've seen plenty with intermittent overheating issues that head gaskets didn't fix (we're talking drives 1,500 miles before ever overheating). That vehicle had head gaskets done twice.

If your truck is high miles already, I would just skip the tear down and go straight for the new block. That is a tough call when it only has 50k miles, but you're taking a gamble when you are paying someone else to do the work.

Another option is to do the head gasket yourself and hope that fixes it. Post pictures of the block on here and let us tell you if anything looks wrong.
 

JohnB

Well-known member
Oct 18, 2007
2,292
12
Oregon
Like to see what test equipment they have to pressure test a block with the heads off and the block not warmed up. Good luck. Had a core block come back once for slipped liners that only had 30K. For fun we blocked up and added 150psi air pressure could never find the leak. Assumed either block was actually fine or needed to be a running temp to leak.
Had a local shop around here that would pull the heads and if his long fingernail would catch at the liner to block it was junk. Think he has several very large sail boats and a yard of parts trucks at this point.
 

3ac3

Active member
Apr 19, 2009
41
0
oceanside
The chances of the shop seeing anything seriously wrong are highly unlikely. I've seen Discos where the liner is visually sticking above the block deck surface, but the vehicle had no symptoms. I've seen plenty with intermittent overheating issues that head gaskets didn't fix (we're talking drives 1,500 miles before ever overheating). That vehicle had head gaskets done twice.

If your truck is high miles already, I would just skip the tear down and go straight for the new block. That is a tough call when it only has 50k miles, but you're taking a gamble when you are paying someone else to do the work.

Another option is to do the head gasket yourself and hope that fixes it. Post pictures of the block on here and let us tell you if anything looks wrong.

The shop was upfront that a visual inspection may not identify the problem. Especially with a liner issue. The truck overall has 102,000 miles on it and the block only having the 50k.

Maybe I'll dive into the HG job but I don't think that would fix the low compression right?
 

3ac3

Active member
Apr 19, 2009
41
0
oceanside
Like to see what test equipment they have to pressure test a block with the heads off and the block not warmed up. Good luck. Had a core block come back once for slipped liners that only had 30K. For fun we blocked up and added 150psi air pressure could never find the leak. Assumed either block was actually fine or needed to be a running temp to leak.
Had a local shop around here that would pull the heads and if his long fingernail would catch at the liner to block it was junk. Think he has several very large sail boats and a yard of parts trucks at this point.

Honestly not sure but they did mention they would have to block off cylinder/heads, etc to properly pressure test. I'm clearly not an expert here...

Based on your post and jymmiejamz should I just assume its impossible to diagnose the liner issue? Basically is the loss in compression only going to be repaired by re-sleeving the block? Or can it be repaired via HG and ring/piston, etc? Obviously that's assuming that those are the culprit... Sorry, I need to educate myself.
thanks
 

Dave03S

Well-known member
Jun 22, 2012
62
2
Seattle, Wa
By the way, for what its worth now, You didn't specify but which OEM 180 degree thermostat do you have? There are more than one with the same PEL500110 part number. There is the grey one and two versions of white called OEM 180 degree stats. I've found the grey one to run 10 degrees cooler than the white ones.
 

jymmiejamz

Well-known member
Dec 5, 2004
6,008
361
35
Los Angeles, Ca
The liner does not hold in coolant. The liner is a steel sleeve that is pressed into the aluminum block. If the liner were to move you would only get noise. Usually there is a crack in the block (almost always on the middle four cylinders) that allows compression gases past the liner and into the cooling system. You could pressure test the block with no liners and it would hold pressure.
 

specops1526

Well-known member
Jan 17, 2007
845
11
Los Angeles, CA
By the way, for what its worth now, You didn't specify but which OEM 180 degree thermostat do you have? There are more than one with the same PEL500110 part number. There is the grey one and two versions of white called OEM 180 degree stats. I've found the grey one to run 10 degrees cooler than the white ones.

This. Only get the grey Genuine one. I think the white ones are OEM and don't seem to give the same results as the grey one.

Also, even if a liner is slipped, I don't think it would necessarily mean your truck would overheat. I thought I read somewhere that you'd get some noise but for the most part, that's all. JimmyJamz could probably confirm.

One of my 04's had a block replaced under warranty due to a liner slip and it never overheated. I just got a CEL and brought it in. The next think you know, my truck is at the dealer for 3+ months waiting for the new short block.