Running Hot - Coolant Level Fluctuation
Thread Starter
|
Senior User
Joined: Oct 2009
Posts: 173
Likes: 0
From: Wisconsin
Running Hot - Coolant Level Fluctuation
ambient temp = 70 degrees F
towing 5000# boat
highway cruising 70-75 mph
power a little weak
no codes
no puking
no smoke (white or black)
fuel economy was about 2 mpg lower than normal
Before yesterday I have never seen my ECT higher than 202 degrees F. Yesterday it quickly climbed unusually high up to 218 F with the EOT getting up around 228. I slowed down a bit and it if I kept the rpm below 2k them ECT temps would drop back down in the upper 190's. As soon as I would get on it to pass or go up a grade, exceeding 2k rpm, the temps would quickly climb back up. Even at much lower speeds the temp climbs rapidly if the rpm's are up over 2k.
I stopped to check things out and the coolant level was down near the bottom of the degass bottle. I let things cool down for a while then I started the truck and idled a bit and the coolant level came back to the min line, where it should be.
Where was all that coolant when it was running hot?
And, where do I start looking for the over-temp problem?
towing 5000# boat
highway cruising 70-75 mph
power a little weak
no codes
no puking
no smoke (white or black)
fuel economy was about 2 mpg lower than normal
Before yesterday I have never seen my ECT higher than 202 degrees F. Yesterday it quickly climbed unusually high up to 218 F with the EOT getting up around 228. I slowed down a bit and it if I kept the rpm below 2k them ECT temps would drop back down in the upper 190's. As soon as I would get on it to pass or go up a grade, exceeding 2k rpm, the temps would quickly climb back up. Even at much lower speeds the temp climbs rapidly if the rpm's are up over 2k.
I stopped to check things out and the coolant level was down near the bottom of the degass bottle. I let things cool down for a while then I started the truck and idled a bit and the coolant level came back to the min line, where it should be.
Where was all that coolant when it was running hot?
And, where do I start looking for the over-temp problem?
Thread Starter
|
Senior User
Joined: Oct 2009
Posts: 173
Likes: 0
From: Wisconsin
The coolant level is still back at normal level today.
Elder User
Joined: Sep 2004
Posts: 821
Likes: 1
From: Nashville
I think the system can expand enough when it gets real hot that the degas bottle will appear almost empty. Then when the engine cools and contracts, the coolant gets pushed back into the degas bottle. If you aren't losing any coolant then I'd check the fan out. It should have come on when you got that hot.
Posting Guru
Joined: Jan 2009
Posts: 1,321
Likes: 0
From: Mattawa Washington.
Have you checked for blockage in the cooling fins of the radiator due to bugs and debris? Might also check for a loose tensioner pulley spring. As Moebdick stated you should have heard the fan come on at those temps. Could be a bad wire connection to the fan, any one of those higher temps. would have told the computer to engage the fan so I would rule out sensor..
Posting Guru
Joined: Jan 2009
Posts: 1,321
Likes: 0
From: Mattawa Washington.
You guys are typing faster than me...lol... the fan is variable speed but at those temps. it should have been fully engaged..Have you unhooked your egr. valve? On later models it has been documented to affect how the fan engages. You are right on the border line of years that affects. ( mainly 05 and newer..)
Post Fiend
Joined: Oct 2009
Posts: 12,123
Likes: 35
From: N. Fort Worth, tx
Trending Topics
Thread Starter
|
Senior User
Joined: Oct 2009
Posts: 173
Likes: 0
From: Wisconsin
How do I test the fan clutch?
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)
Brett Foote
Top 10 Ford Truck Tragedies
Joe Kucinski
AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make
Brett Foote
Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!
Michael S. Palmer
Ford's 2001 Explorer Sportsman Concept Looks For a New Home
Verdad Gallardo
10 Best Ford Truck Engines We Miss the Most!
Joe Kucinski
2026 Shelby F-150 Off-Road: Better Than a Raptor R?
Brett Foote
2027 Super Duty Carhartt Package First Look: 12 Things You NEED to Know!
Michael S. Palmer
10 Most Surprising 2026 Ford Truck Features!
Joe Kucinski
Hotshot
Joined: Jul 2005
Posts: 13,834
Likes: 25
From: Middle Tn.
That does sound like a possible t-stat sticking. It also should not rebound that low.
Thread Starter
|
Senior User
Joined: Oct 2009
Posts: 173
Likes: 0
From: Wisconsin
Well 69cj, it appears that you nailed the root problem! Thank you! Tonight I replaced the t-stat, hooked up the trailer, and headed for the freeway for a test run. Once she was warmed up I romped on it much harder than my normal driving and she stayed nice and cool! I can't say that I can see anything wrong with the old t-stat but the new one seems to be letting the coolant do it's job.
Thanks for the replies, everyone. I am still going to take it to my mechanic to have the fan clutch tested, but I think at least one item is crossed off the list.
Thread
Thread Starter
Forum
Replies
Last Post
ginomachino
6.4L Power Stroke Diesel
9
Aug 18, 2016 09:13 AM
shultzaberger
1983 - 2012 Ranger & B-Series
20
May 10, 2016 05:19 PM
