I've spent some time reading, but still need a little help.

About 3 weeks ago we finished the install of our new engine. It's my understanding that the engine has been running around the 199-201 mark on the highway since the we finished. Over this past weekend we had temps in access of 215 degree's while driving on the highway. The day time temps were in the mid 80's on both days, and we did highway driving the entire time.

When installing the engine we replaced the radiator, hoses, t-stat, and temp sensor. I'm pretty sure we have all the air bubbles out, and the coolant level hasn't changed since we finished everything up.

Any help would be greatly appreciated.

 

At the risk of asking the obvious; did you install the Grey 180* T Stat?

 

That's what I need to verify tonight. I pulled a grey 180* out that I had previously installed (2 years ago), but I can't remember what the color was of the new one we put in. I'm pretty sure it was grey, but won't be 100% until I check.

I should also put out there that we have a winch, and roof rack on it. I'm not sure how much if any impact that would make on the temps.

 

Hopefully that's your issue, I chased similar temps in my D2 until I installed the Grey T Stat, now she runs at 186-188 pretty consistently

 

I think I may go ahead, and pick up a new one since they're not that much. While I'm at it I may also pick up a Napa sever duty fan clutch (TEM 271656) to replace the original one that's on there.

I've got until the end of June to get this figured out, but hopefully it won't take that long.

 

I just found a picture of the t-stat that I installed, and it's the 180*. I'm not sure if this new OEM t-stat could have failed? Is it worth replacing again, and bleeding down the system again?

 

I'd say you have an issue if you were running 199 on the highway. with a proper bleed you should have been down to 188 highway and 199 idle in traffic.

With system bleeding "pretty sure" isn't good enough. Damn sure is what you need.

You need to check the bleed screw each morning before you start it up, if it has room for more coolant at the bleed screw you found a small air pocket. A thimble size amount of air will cause a 10 degree difference in operating temps. Once you get to the point where you don't need to add coolant into the bleed screw hole because its still full, then you can be damn sure.

Also while doing this some suggest running the heat on full a few times during the day, then check through the bleed screw the next morning just to make sure the heater core is clear of air bubbles.

If you never do stop having to add coolant in the morning this way, then you have another issue regarding where the missing coolant is going or air is getting in. Usually air does not get in unless coolant goes out, in a perfect world.

The other thought I have is that the winch may be blocking air flow to your radiator causing the recent spike on the highway.

However I've noticed on hot days, above say 90 even with the air completely bled I will get up to 210 on steep hills under load, then the fan kicks in and knocks it back down.

The major part of your problem though is that you haven't yet got it down to 188 on the highway.

If you are Damn Sure you got the air all out and you still arent at 188 highway then you may have a bad stat or the wrong one. You can test the opening temp in hot water on the stove. Bad stats do happen, right out of the box. Lucky 8 replaces them if you got yours from there.

 

I'm not damn sure, and that's why I'm here asking. With everything I've been reading I'm leaning towards needing to bleed the system again, and possibly changing the fan clutch.

I'll take the bleeder off when I get home tonight to see where the coolant level is. If I'm understanding you correctly the coolant level at the bleeder hole should be full. In other words the bleeder should be topped off, and not able to accept anymore coolant?

I also understand the point of running the heater, and in my situation that should get done. Since everything was completely disconnected there very well could be an air pocket in that area.

I'm not overly concerned about the coolant missing issue. The coolant level hasn't changed since the day after the initial drive, and the system holds pressure via coolant system pressure tester. The reservoir and cap were also replaced a couple years ago so those should be OK too.

The other issue would be the fan. Our temps were going up on small climbs, and temps didn't start coming back down until the climb was over. Once we were on flat ground, or coming down hill is when they came back down. If we let off the gas the temps came down, but under load there didn't come down at all. This is the reason I'm going to look at the fan clutch to make sure it's in good working condition. I'm still leaning towards replacing it with a Napa Severe Duty clutch just for the piece of mind.

Someone on another forum is who made the comment about the higher temps with a winch on the front. I can see it blocking a little, but it hardly sticks above the top of the bumper.

My to do list looks something like this:
1. Check coolant level at bleeder
2. Add coolant to bleeder if necessary
3. Run with heater on to clear bubbles in the heater core
4. Repeat 1-3 if necessary to ensure full system (proper bleed)
5. Check fan clutch and replace if necessary

If temps are still running high:
6. Check t-stat and/or replace with known working t-stat
7. Properly bleed system
8. Repeat 1-3 is necessary to ensure full system (proper bleed)

Thank you for all the information you provided here too!

 

The fan wouldn't make any difference in temps on the highway... it's pretty much all airflow from driving at that point. So unless you're temps are too high at idle, I'd leave that alone.

Get a non-contact thermometer and point it at the radiator after you've gotten up to temp. Should see 5-10 degree max variance from top to bottom.
Also point it at the t-stat, if its way cooler on the bottom than the top, then it may be clogged or not working properly, causing the flow to skip the radiator circuit.

I had a bum genuine grey tstat out of the box. Caused 217 highway temps, 224-230 idle.

For what its worth, I've never ever seen sub 200 temps. And my entire cooling system is brand new. I currently have a motorad 180 in there and am getting 202-212 temps

If all that stuff checks out, I would suspect the water pump is not delivering enough flow, because you said the temps kick up when under load/speed. My idle temps are always quite a bit higher than at speed.

Side question, do you work for BROG? I received some stuff from them last week and really like it. Plan on ordering more soon.

 

Just to be clear, never open the bleeder when there is any heat at all in the engine compartment. If you are driving it today, DO NOT open the bleed screw when you get home.

Open the bleed screw only when the engine is stone cold before you start it.

Otherwise the system may still be holding pressure and opening the bleed screw at that point would be counterproductive.

I've had to bleed a few times lately and can say from experience this method may take four or five days of checking the level at the bleed screw before it did not need topped off. And even then it is literally low maybe a thimble full of coolant. You will not notice the level being a thimble quantity low in the overflow tank. You can only notice this in the bleed screw hole. So don't go by what you see in the tank as a reference in this case.

Also with temps around the mid 50's here in Seattle it still takes my truck several hours to cool down. Like it was still warm 5.5 hours after driving it to work. This is why I say check first thing before starting the engine when it is stone cold.

STONE COLD IS VERY IMPORTANT!

I used a small funnel to add coolant in through the bleed screw but you could also use a paper cup and pinch one side into a V shape. Then yes top it off so that it won't accept any more coolant. Repeat until you no longer need to add even a minute amount.