MKS temp gauge.

[ChaudMasterFlex]

I have a 2014 MKS ecoboost and I’m having an issue where the temp gauge randomly drops while driving. It never goes above the “normal” spot, but always drops with no rhyme or reason. Sometimes it’s just a single step down, other times it drops quite significantly. Temps seem normal number wise (cruising 194-200, and jump to 209-210 when idling). I put a new 170 t-stat in yesterday and spent about an hour trying to bleed it (hoses weren’t collapsed, both were hot). Felt like I lost more coolant than I put back in too. It’s doing the same thing with the new t-stat (feels like it’s doing more tbh). Also, water pump, chains, guides etc were changed 1k miles ago. It’s driving me nuts, any ideas?

 

[Tbird6]

Even with bleeding maybe you still have air in the system?
Just a guess.
Drive it some more and put it thru several hot/cool cycles so see if that helps?
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[kryptto]

Even with bleeding maybe you still have air in the system?
Just a guess.
Drive it some more and put it thru several hot/cool cycles so see if that helps?
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I agree, proper bleeding will be essential.

OEMTOOLS 87045 No Spill Coolant Filling Funnel Kit with Coolant Tester, No Spill Coolant Funnel Kit, Coolant Tester Kit https://a.co/d/4JniiDg

 

[Tbird6]

Actually the correct tool is to use a vacuum re-filler. Then no burping is needed.

I just got one and it makes all the difference in the world. I don't know why I waited so long to get one as they are not very expensive either.
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[Ta2dResqr]

I found that this was one of the harder cars I have owned to bleed. The procedure calls to heat the motor up through one fan cycle, increase the rpm to 3500 for 30 seconds, idle for 30 seconds, off for 1 minute and repeat 5 times. It seems to have helped mine a lot.

 

[kryptto]

I would like to add to get those internal controls on high and make sure you run the coolant through the heater core.

 

[ShatteredMJ]

Or, there is this other irresponsible way of not fully filling the reservoir while leaving the cap loose and driving around for a while then letting the car cool down with the cap open. Bubbles solved.

 

[ChaudMasterFlex]

Yeah, I bled it for another hour same issue. I haven't tried everything suggested above yet. I had an employee that swears bleeding these is more challenging than most cars he's dealt with. Thanks for the replies.

 

[Tbird6]

I think he is right? Many late model cars are a pain to bleed. But the vacuum filler does a great job. One and done. No air pockets.
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