Been chasing phantom cooling temp problem

[grizzlyls]

Everything will work fine and no leaks for weeks then bam over heat indicates, but no real over heat issue. Traced one small issue to the o ring on the GEN alum Tstat housing. Make sure that thing is cooled down so its shrunk to stay in the cap. DO NOT set it on top of the housing and close - it wont seat right sometimes.

Anyhow I am starting to suspect CHT sensor (V8). Mech showed me a trick using infrared temp sense unit to try and isolate issues and where. This morn I am showing 230 degrees on the phone, with hydro fan (gen 1) doing about half speed (by its loudness I guessed) and it stays stable there for about 5 - 10 min while I test and prod.

All hoses and housings look in normal ranges, but I find it odd that the hoses (hot) are reading about 200. Investigating on internet it suggests real inside temp of coolant is about 10 degrees or so up - which walla that would be 210.

Am I thinking right? How can I test the sensor? Do they go bad like this? I ran 3 weeks normal in hot days and cools days since the last phantom issue, this weekend it is real cool so something seems off.

 

[Gary Vogeler]

Grizzly, I have similar questions I raised in a response to thread:

what is the runing temp of a 06 lincoln ls 3.9l

I'm beginning to wonder if there is an adder in SW that the logic uses for the fan operation. It's easier and less risky to make adjustments to one SW parameter (engine coolant temp) than to alter multiple lines of logic, especially if the end user will not see it without a scanner.

I've been powering on the OBDLink MX prior to engine start (before Sun up) and have seen at least 5 times where the coolant temperature is ~13F higher than the outside ambient. I'm going to keep monitoring in the coming weeks but every morning, I see the same offset. One heavy overcast/rainy afternoon I even saw the offset after work, engine had been off that day at least 10 hours. I can't trust the data after Sun up, I'm going to rely on the morning data.

Most posts include data once the engine is at temp. I had little success in finding pre-engine start data. Your infrared data is interesting and a good check against pre engine start data.

I'm not seeing overheats in my 02 V8 sport. Temp gauge has stayed at mid-line even when OBD tells me I'm at 228. I expect the 228 number to rise as summer sets in.

If your monitoring with a scanner, would be good to know what you see prior to engine start in addition to your infrared findings.

 

[grizzlyls]

temp gauge on mine doesnt start to move until well in the 230's. While I was testing/bleeding today it sat at 3/4 and that was 241~243. Cel command center has not thrown an overheat yet.

I am using the old heater on full trick to survive the weekend. Gonna have to leave it at the mechs tomorrow, tired of instability and its going to get hot (weather) soon. If it isnt the CHT, then as best I know its the tstat which is just over 1 year old, or the water pump which isnt even 6 months old.

I dont know, but from what I can tell all the hoses read the right temps (cool or hot depending on position).

 

[RigsLS]

Do check there is no caked on crap in between the radiator and cooler. I found an old torn up plastic bag with hardened caked on mud surrounding the front of my radiator when I first took possession of my 01 Sport. Soaked in between with a running water hose while gently probed to get the debris to drop down. Gave it a complete cleaning after that. Ensured plastics underneath was solid and provided the required air movement within the shroud area.

 

[Leblanc5]

May or may not help but the coolant runs through the DCCV which is a finicky little part known to cause a number of problems. Not saying to replace it but as others may disagree, it can be cleaned just as it can become dirty. Considering the year of your LS, I used three needle nose pliers to pinch off the three hoses going to it. Disconnected the battery before unplugging it and removed it. I found the ports plugged and one valve was frozen. In my case this naturally was the issue but had I owned the vehicle and known as this part was serviceable I would have done so. You can flush the ports and free up the valves. Ensure the seat and stems are in good shape as well as all sealing rubber parts as the keep fluid from getting to the solenoids. I had a spare USED DVVC that I dismantled before hand that I got very cheap from pull a part! Seems like a lot but it really wasn't a hassle at all and it saved me a great deal of money! Sorry for carrying on, just passing on my victory story in hopes that it just might help. Best of luck