[Flick]

[color=rgba(0, 0, 0, 0.701961)]     Driving on I90 West from Spearfish, SD to Billings, MT. Towing 2006 Jeep Wrangler Unlimited. Within 10 minutes of starting out the coach began to climb in temperature above the 190 red mark to almost 210 (see attached). The engine oil did also heat up over the red mark for a few minutes then settled down.  I don't know who marked this gauge this way. Now the grades were not steep but were gentle hills. We hit a couple 6 percent but that was later in the day.  We were averaging about a 62 MPH and running about 1,600 RPM.  I got worried the heat would damage the engine so we pulled over and disconnected the Jeep. Drove another 60 miles and the engine cooled down to about 185 on the gauge. I also had installed a digi panel gauge to more closely monitor temps. The digi is consistently 15 degrees cooler than the gauge. It also measures transmission temp. The regular gauge showed that at 210 - 220 while digi said a steady 175.[/color]



[color=rgba(0, 0, 0, 0.701961)]So first question is can these old gauges go bad? Trying to decide which one I should trust more. [/color]



[color=rgba(0, 0, 0, 0.701961)]Next question is what temp should I try not to exceed on the engine or is there a point where you say if you exceed this temp for X time stop and let the engine cool. When I stopped the engine it cooled right down and went over 190 on the old gauge again just a couple of times on big hills after we unhitched the jeep and drove it. I kicked the speed up as well to 65 with 1,800 RPM. Grade of road was the same and maybe even hillier. I will hook the Jeep up again tomorrow and try again. I don't think I missed anything in that. We have towed it before as well as a car trailer with no issues. The temp may spike on a hill but settles down again. Oh and I am topped off on radiator fluid so that's not an issue. [/color]



[color=rgba(0, 0, 0, 0.701961)]Lastly on dead flat roads at 65mph with not much wind the turbo never went below 5-7 PSI. going over simple bridge overpasses it would go to 15 psi. I have never watched this before. I think I have power but wonder if I should change fuel filters just the same. If she is beginning to clog in the filters will that make the turbo run more and thus get hot?[/color]

[encantotom]

hi todd,

a couple of things. the analog temp guages have been know to at best be hard to read (they are not linear) and i think you would be hard pressed to tell temps in between the lines within 5 degrees even if they were accurate.

what did your digigauge say for engine coolant temp? you only mentioned oil temp for it.

they are also not always accurate. on my 90, the temps on vmspc were what i went by and not the dash gauge.

i had a friend tell me his non ddec hardly ever got above 190 even pulling steep grades. that seems unlikely to me.

someone who has one of your vintage will need to weigh in. i believe there is a yellow and red warning lights on your dash. yellow means watchout, your temps are getting too high and red means stop now....and at least on the ddec engines, it will shut your engine off in less than a minute. (there is an overirde switch so you can get off the road)

i am not familiar with the digipanel, but they claim it is accurate within a degree.

i always panicked if my 8v92 got much over 200. i believe at 205 you get the yellow light and somewhere between that and 210 you get the red shutdown light.

running straight and level, 175 sounds low as well unless it is really cold outside. i think you probably have a 180 degree thermostat (is that right guys?)

tom

[Flick]

Tom the digi engine water temp was always about 10-15 degrees cooler than the regular gauge. The temp yellow light never came on. From the red tape it looks like someone was trying to say don't go above 190.

Tom I have had clogged filters before and it was obvious because there was little to no power. I am not at that point at all as I can still accelerate but not sure if there is some degradation in power. Would a clogging filter contribute to the engine working harder and the turbo boosting up the temperature?

I read that article again Michael sent out a bit ago but it does not talk about how hot is safe and for how long. I suppose I just need to see that light come on and know I am close to having an issue. I am paranoid to damage an engine I just had rebuilt 2 years ago as you can tell.

[Flick]

I have read several times now to make sure the radiator is occasionally cleaned (outside). There is a truck wash 10 minutes from me here in Billings. If I drive over there and they have a self serve wash how are they best cleaned? I assume just spray it good from inside to the outside first then from the outside.

Trying to think of everything I can do here so I may just change fuel filters as well as I have 2 extra sets with me.

From what I read on the net I think I managed the high temps ok by downshifting for the most part. Never had a warning light come on. Also if I manage this by the digi panel and not the original temp gauge then it was hot but not over 210 and the spikes cooled down much quicker on the digi than the original temp gauge.

[HoosierDaddy]

Todd,
The fan blows the air out the back. That is why we have to be vigilant. Any oil leaks from the drive-train tend to get pushed through the radiator by the fan. I would get some degreaser (ie Simple Green etc) and soak the radiator first then blow from the back of the coach through the radiator into the fan with the spray. The build up will be on the engine side of your radiator. A truck garage may have a steam cleaner. That would be better yet.
Typically a clogged fuel filter will have the same effect as the driver letting up on the accelerator. Less power. As long as you can maintain RPM engine cooling should not be affected.

[rheavn]

Todd,
If you have a infrared heat gun, try measuring the radiator fin area temperature.  This should give you a true idea of which gauge is correct without guessing. This method worked for me when I had a coolant temperature gauge go bad.

If you don't have one you need to get one as it is a very useful diagnostic tool. Also they are inexpensive.

Good luck............................

[Fulltiming]

Todd, 180 should be running with the thermostats closed and about to open so it would be a minimal temperature you would typically see after engine warms up unless someone has changed the thermostats for lower rated thermostats which is not a good thing either. Engine temperature driving on a hot day running with a fully loaded coach will typically be in the 190 range hitting 195 on small grades. Mountain grades (6% and higher) will result in the temperature rising quickly. I run off of the VMS-PC digital gauges, not the dash gauges. I start slowing down and downshifting about 200 degrees and and try to not let my engine temperature ever exceed 205. I have never had the yellow warning light come on by keeping the digital gauge at 205 or below. Anything above 205 on the digit gauge takes away room for error. Although 210 will likely not damage your engine, I would NOT let my engine get that hot. No reason to.

Certainly keeping the radiator clean is important on any coach. As Dean said, any oil leaks will result in the fan pushing the oil directly into your rear radiator and will dramatically reduce your cooling capacity. I use a digital infrared thermometer to scan back and forth across my radiator starting at the top and slowly moving down the radiator with each horizontal pass to make sure that there are consistent temperatures side to side and that the temperature drops as the water moves to the bottom of the radiator. The use of simple green on the inside of the radiator before steam cleaning or very careful pressure washing is very helpful. if you get too close to the fins with a pressure washer you can do more harm than good by blasting the fins so hard that they bend closed, just what you don't want to do.

The marks on your gauges are NOT maximums. I don't know who put them there but I would remove them as they are confusing and cover the needles up at the time you need to see them the most.

[ccjohnson]

I understand you completely! We have always had some similar issues with our coach. One time on our way to Yuma we had some over heating issues. Stopped at a shop & had radiator steam cleaned. It helped quite a bit. You could definitely visually see areas that were plugged with dust/oil material. When we first got coach, blower went bad & pumped a bunch of oil out that got sucked through radiator. On my latest ordeal, fan came apart & damaged radiator. When repaired Stewart & Stevenson shop said that on test drive highest temp they saw was 193F. They measured off DDEC. They told me our gauge was showing +/-12F high. Spent a lot of time in 22nd & 3rd driving from Kingman to Grants after that due to my paranoia of high temps. I have since got Silverleaf but have yet to take the coach out to try it. I tried the run an independent ground trick with limited success. I will get a new analog gauge if my Silverleaf confirms that it is not accurate. I have used temp gun on radiator and thermostat housings to satisfy myself that the gauge was reading "hot". But still have the paranoia. My gauges are all original as best I can tell so at 23 +/- years I guess they can be expected to hit the end of serviceable life at some point. Based on my experience I would say check with a temp gun. If it confirms DIGI gauge readings, go by them & replace dash gauge when you can just for the peace of mind of having both give you the same information.

[whatsnewell]

I have a 6V92 as you know Todd, so my experience may, or may not help. On the flat my 6V92 runs about 185-190, and when we climb a long grade it will get just over 200....that has been the norm for the 7 years we have owned the coach. I do clean my radiator every few months, or when I see the temps begin to run 4-5 degrees hotter than normal. I was told not to use Simple Green as it is not friendly to aluminum, but I do use a citrus based degreaser (can't think of its name right now) when I don't have access to a steam cleaner. The steam cleaning gets the best results.

[Flick]

Todd,
If you have a infrared heat gun, try measuring the radiator fin area temperature.  This should give you a true idea of which gauge is correct without guessing. This method worked for me when I had a coolant temperature gauge go bad.

If you don't have one you need to get one as it is a very useful diagnostic tool.  Also they are inexpensive.

Good luck............................

Wow ow I have one and did not even think of that. Brilliant idea thanks I will try that. Now Tom mentioned the yellow light warning and then the red light. All I have is the yellow dash light. Could that be the one minute warning to shut down or simply the warning light. Should I trust it?  It never came on.