Intake Manifold Temp

[rpasetto]

We took a short outing, the first after a few months.  I noticed my ISM500 Intake Manifold temperature,  rising to 140F, sometimes 150F on hills.  The reading came off my VMSpc.  Meanwhile the engine and trans temp ran the normal 180s to 190s.  When I got back I did a cleaning of the CAC, Radiator area using a Dawn solution/Simple Green mix.  Was expecting to see a lot of dirt come off but the drippings were clean.

We're still in our first year with this coach; I do not recall this happening last summer.   Nor do I recall such temps with our old  Dynasty ISL.

Recommendations will be appreciated.

 

Update:  Checked VMSpc for recent diagnostic events; none shown. 

Edited March 26, 2021 by rpasetto
updated

[jfbolkovatz]

R.  On our ISM 500 the intake manifold temp runs normally 15 - 20 degrees above the outside air temp. With increased turbo boost the temp would be higher in the hills.

JoeB 03 Exec

[planodp]

We just came back from Big Bend National Park. My ISM 500 was running in 154 degrees, as I was getting closer to Big Bend and start to claim I did notice that Engine load would be around 100% and 30+lbs boost and the Intake air temperature was at 174 degrees. Engine and Transmission was in 180-190 degrees all reading came from BlueFire. 

 

[rpasetto]

6 minutes ago, planodp said:

We just came back from Big Bend National Park. My ISM 500 was running in 154 degrees, as I was getting closer to Big Bend and start to claim I did notice that Engine load would be around 100% and 30+lbs boost and the Intake air temperature was at 174 degrees. Engine and Transmission was in 180-190 degrees all reading came from BlueFire. 

 

It looks like your experience is very similar to mine.  So the question is, are temps over 150F expected when climbing hills?  My boost yesterday was about 31psi when I saw Manifold Temp going 150F+.   Either we both have the same problem or it's not a problem at all, I'm puzzled.  

Questions to the group:

  1. What's the expected temp rise on an ISM on a hill climb with 30+psi boost? 

  2. If 150F+ is not normal could it be a bad intake manifold temp sensor?

[Pepperell]

I haven’t got a gauge for this on my 400, but it wouldn’t surprise me to be that high under those conditions.  Ambient temperature at 2 feet above the street on a hot day is likely some amount above 100.  The ambient temp in the engine bay is likely higher than that.  The cac probably doesn’t cool the hot turbo charge down to ambient.  The manifold is bolted to an engine block that’s at 185F.  I’m not surprised it is running at 150+ under those conditions.    

Edited March 27, 2021 by Pepperell
Added last three words

[BradHend]

2005 Cayman with the 5.9 ISB engine. 
Traveling from Ontario to Nova Scotia this week and it’s really the first real long run since I completed all my turbo, EGR, coolant line work etc last year.  
While traveling on flat as water sections of the 401, my Bluefire is reporting intake temps of 140-150 degrees Fahrenheit while travelling at around 65MPH. Boost holds steady at around 12-15 PSI on these flat sections, and even when climbing the little hills that I did today, intake temps would sometimes climb up to 160, with 30 lbs of boost.  
Anyone with this same engine able to report what your numbers are? I feel like that’s too high and I’m rather annoyed as I put a lot of time and money into this thing and thought she’d be working a little better.  Reman Holset turbo, reman EGR valve, all new turbo and radiator plumbing, new coolant, removed rad and CAC and cleaned the heck out them among a host other fixed.  Just not sure what to think.  Thanks for your input. 
 

I don’t know why that uploaded upside down.  

Edited July 13 by BradHend

[Bill R]

On 7/12/2024 at 7:03 PM, BradHend said:

Anyone with this same engine able to report what your numbers are?

Brad - I do not have the same engine, but you can look at QuickServe for your engine and find what your CAC spec performance should be.  For the 400ISL, my coach's engine, the air intake temp should be no higher than 40F above the ambient intake temperature.  A couple of years ago my intake temp started to climb and it was the result of a bad intake temps sensor.  Something to consider.