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spankyjr1, Journeyman
Category: Medium and Heavy Trucks
Satisfied Customers: 2598
Experience:  I worked on all types of equipment semis,forklifts,farm,ect.
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I have a 2008 gulfstream tourmaster motorhome (diesel

Customer Question

I have a 2008 gulfstream tourmaster motorhome (diesel pusher) with a mercedes MBE900 engine (330HP) on a Freightliner chassis. Just bought it with 42k miles and in great shape. One drive from Orlando to San Antonio I noticed the overheating alarm come on and we pulled off added .75 gal of coolant and kept the speed at 60MPH with no further issues. Took it to Freightliner when we got back (week ago) for PM Engine & Genset (Caterpillar Powertech 8k), a coolant flush both, all new filters, and checked all systems. On the test drive at 75 miles an hour it will overheat unless you slow down to 60/65mph. Tech tested the fan clutch which is working properly and is telling me it is either the radiator needs replacing or the water pump needs to be replaced. I decided to not have them do any more work and drove it home.*****at 65 miles an hour and the temp needle was a hair over half. I did run it up to 75MPH and it did heat up just as the tech said it did.
Hopefully one of you guys have seen this before and knows the answer
Submitted: 1 year ago.
Category: Medium and Heavy Trucks
Customer: replied 1 year ago.
Also replaced were: MBE900 Diesel Engine
1) primary fuel filter / water filter (x2)
2) Air filter
3) thermostat
4) Fuel Filter ( x2 )
5) Oil filterMBE900 COOLING SYSTEM
1) Change thermostat
2) flush sysytem
3) new coolant
4) new o rings
5) new clampsFan Clutch Test:Fan comes o at 200 degrees and stays on, bus got hot at 212 degrees, fan shuts off at 190 degrees at 70MPH. back at shop Steam Clean radiator through front air cooler radiator, some dirt did come out. Road test after cleaning rad, ran at 75MPH and temp now went to 223 degrees and overheat coolant temp light came on. Bus back to yard. Two road tests identified fan and temps.......come on and go off.Freightliner thinks it could be either bad water pump or radiator needs to be replaced.Comments please........
Expert:  spankyjr1 replied 1 year ago.
Hi, my name is ***** ***** you for your question.
Sorry for long delay.
I would do one test first its called a Combustion gas leak test.
You can pick up a test kit at a local auto parts store or order online.
It's possible you may have a egr cooler or head gasket leak into cooling system only when under full load, which your engine is at 75 mph.
If this test is okay then yes I would agree it would need a radiator not a w/p.
A w/p will either work or not or leak, but a partial blockage in radiator is more likely. A bad w/p would act up more at lower engine rpm not high rpm and higher road speed you get more air flow across radiator.
I just don't want you putting a new radiator in and have same issue.
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Expert:  spankyjr1 replied 1 year ago.
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