Engine temperature running hotter then normal.

[M&EM]

I’d like some help trouble shooting this recent (past 3 months) occurrence of hotter engine operating temperatures.

PRESENT ENGINE/COACH HISTORY:

2003 coach, WH build 10/2002
63kmiles
Oil changes every 3-4 kmiles.
coolant changed at 3 1/2 years using Dex.
T stat never been changed.
Actia temp gauge has never varied from center point after warmup under any operating. condition prior to this year.
Engine coolant temperature also monitored directly with AutoTap scan gauge and has been. observed to fluctuate between 190 and 230 F under any of the same conditions as above.
Fuel filter changed last week.
Fuel pressure at 60 psi as of last week.

NOW:

Scan gauge and Actia Temp gauge both indicate much higher operating temperatures under hill climbing loads of 4- 6 % and for more then about a mile--as high as 240+ F and within 1 increment of red line.

This increase is noted with AND with out the dash air conditioning on.

The fan clutch can be heard to come on sooner if the dash air is used while hill climbing.

When the fan clutch comes on, the engine temperature maxes out just above 245F and the Actia gauge is just about into the last increment of the gauge( not into the red yet).

While this is happening I am manually in 3rd gear and holding rpm at or below 3300 RPM. I did this to help the fan clutch “catch up”. And it seemed to reduce heat generated. I still had plenty of throttle to pull the hill but If I left it be in auto it would want to down shift and lower the fan speed.

No abnormal temperatures except on the long hill pulls. Scan temperature shows 200 to 220F for all other driving even in traffic and with dash ac on.

During the above I can hear the fan clutch roar occasionally while ambient temperature was between 80 and 100 F as these were the temps we went thru on our travel to San Diego.

These items were the observations on this last trip from Phoenix to San Diego yesterday.

I am thinking 1) the thermostat is not opening fully. 2) the fan clutch is mal-performing.

PS I also monitored O2 sensors and saw the average sensor voltage around .4 -.5 volts
After the fuel filter was changed( was 90% blocked)Full power was restored but high temp still persisted.

If we make it back to Az I will start with the Thermostat replacement and see if there is an improvement.

Anybody have some added thoughts?

Thanks
Marty

[dieselclacker]

Marty, at what temperature does your viscous clutch fan kick in and begin to really roar. I believe most owners report around 209 degrees F for this event. I know mine would begin to roar at this temperature, before I installed a cooler thermostat, and it would drop the engine coolant temp on the scangageII back to around 190 in just a couple of minutes. I would suspect the fan rather than the stat. If the thermostat was bad, I would think it would run hot all the time and not just on hills.

Dieselclacker

[M&EM]

Quote:

Originally Posted by dieselclacker Marty, at what temperature does your viscous clutch fan kick in and begin to really roar. I believe most owners report around 209 degrees F for this event. I know mine would begin to roar at this temperature, before I installed a cooler thermostat, and it would drop the engine coolant temp on the scangageII back to around 190 in just a couple of minutes. I would suspect the fan rather than the stat. If the thermostat was bad, I would think it would run hot all the time and not just on hills. Dieselclacker

Thanks dc,
Hard to say for sure. I should add this to my observations in response to the t stat. This past trip I was watching the scan indicating eng temp at 200-220 and don't recall much fan activity UNLESS dash air was on. The harder I used the AC(higher ac fan speeds)the more frequent the roar in that temp range. So the condenser in front of the radiator package is throwing heated air at the fan clutch enough to activate it more so then the engine. My reasoning to the t stat was based on the slower hot water flow from the eng to the radiator at easy driving If t-stat was not opening fully. Lower water flow may cool quickly enough at low throttle and highway speeds on level roads to keep temperature at the fan clutch below its trip point.
What seems different now then a year ago is that the eng temp now never gets down as low as 190F even going down hill at 65 mph for long downgrades. My aging memory tells me it used to. This effect would seem independent of the fan clutch activity.

That is why I probably am hoping for a simple/Less costly cause. I agree that the fan clutch is very strong candidate right now. I am prepared to have to replace the fan clutch if the t stat change doesn't help. I'm waiting for Mike at Brazel for some info regarding the correct fan clutch and costs.
Perhaps there will be some additional posts of other possibilities.

Marty

[Full-Timers]

Check the exterior of the radiator for restrictions. You may have just picked up a piece of paper or something.
Make sure your cooling system is full. If you have air in the system you can get a steam pocket.

[M&EM]

Thanks F-T,
I checked the overflow tank level cold and hot and cold several times over passed several weeks and yesterday. The level changes by at least an inch as it should. Cold it is always back down to the same lowest level. from what I understand, the radiator should be full or that level would decrease. The cap has not been removed in over 2 years. I have assumed from that that there should not be any air trapped and that the cap is still functioning correctly. I have not actually tested the cap.

Marty

[Dave Rickey]

You should get a full coolant system flush, and check the thermostat (take it out cool, measure the length, then boil it and measure again, if it expands less than .25-.5 inches, it's broken). If your thermostat isn't opening fully, or there's a bit of plastic in a chokepoint, it would fit the symptoms you describe (so would a failing water pump, but that generally doesn't happen quickly and has some additional signs). Then, your cooling is almost entirely dependent on boil-off (so you always run at or near boiling).

After disposing of the obvious: Make sure you don't have a plastic bag plastered to the front of the radiator. Fan clutch just doesn't seem as likely, it wouldn't explain why you're running comparatively hot at lower throttle.

[M&EM]

Quote:

Originally Posted by Dave Rickey You should get a full coolant system flush, and check the thermostat ------------- Make sure you don't have a plastic bag plastered to the front of the radiator. Fan clutch just doesn't seem as likely, it wouldn't explain why you're running comparatively hot at lower throttle.

Thanks D.R.
Plan on doing just that when I get back to Az Sunday.

Found nothing obstructing air flow to cooling pack. All air dams are in place and well maintained.

Since we will be traveling back along I8 from San Diego Sunday, our plan is to not tow our Liberty until we get past the 6+ % grades going East.

Marty

[JCM]

Keep your rpms at about 3500 - 4,000 when climbing long hills. It helps cool the engine. My fan would kick in at 204.f .

[gbs2320]

I had a thermostat not fully open on my Jeep. Cool at idle but heated up going down the highway even on the level. I pulled the Tstat and could see rub marks on the mechanism showing likely binding stoppage on the opening cycle. Replaced it and all was good. I would replace your tstat first before moving on to other possible causes. Also the 8.1 like my jeep uses a 195 tstat (fully opened at around 212) not a 190 so at fully closed your warmed up temp show not be lower than 195. Here is a clicky on tstats. http://www.crankshaftcoalition.com/w...TATS_EXPLAINED

Another possible cause of your issue might be a partially restricted radiator reducing your flow volume like a partially closed tstat or externally clogged rad cooling fins reducing efficiency. Your fan clutch has specs for temp it starts at so you should be able to find out what that spec is and verify correct operation. My fan clutch is different than yours since it is electro viscous and not ambient temp triggered and it a gas pusher so I can help with info on your fan clutch.

Good Luck. Greg

[RocketDork]

I wouldn't assume that you have enough water in the radiator based on external tank observations. I made the same assumption, and decided to take the radiator cap off one day. I didn't see any antifreeze in the filler tube, so I decided to go ahead and top it off...almost a gallon later, it was finally full.

I checked it often after that and another quart or so of antifreeze was required to get it to stabilize.

Until I reached the "quart low" level adding to the external tank did nothing to change the level of the coolant in the radiator. I think there is a note in the WH manual about this, but I can't locate it right now.

[DriVer]

A tech removed by water heather this past week and my coolant was released. It required close to a gallon of coolant (Dexcool + 50% water) to top off the engine. I ran the engine and observed the radiator burping. Make sure you do this and simply not replace the cap when the radiator appears full.

The expansion tank is not any type of indicator that the radiator is full.

[TrekPR]

A bad radiator cap can also cause the engine to run hotter than normal. I had to keep putting antifreeze in and finally replaced the cap. No more problems.

[M&EM]

Sunday we returned home via I8 from San diego to Phoenix towing our Liberty the whole way.
We left early in a misty rain that ended near the top of the mountains about 60 miles east of San Diego. The weather was cool to cold. Engine temperature at the steepest and longest pull got up to 240. Use of the heater seemed to bring down the temp--although I couldn't be sure since the main fan was roaring pretty good too. No other high temperature conditions occurred the rest of the trip.

Yesterday I opened the radiator cap and found the coolant was topped off. Drained down some coolant and removed the thermostat. Bought a replacement at Napa. Their part appears to be a re boxed Stant. Tested both in hot water with a thermocouple attached to one. Both appeared to start opening at about 196F. Continued to heat the water to boiling about 210 F. Couldn't be sure but appears the new one opens a little further.
Installed the new tstat . Refilled system via one of the heater hoses until radiator over flowed.
Started engine to warm up to operating temperature. Capped it. Filled overflow to hot line.
Today I checked cold radiator. Was full. I'll repeat this check before our next trip in 7 weeks to San Diego again. Thanks all for your suggestions.

Marty

[TrekPR]

Marty,

Your nerves are better than mine, it would drive me nuts to have that high a temperature. Just a guess but it could also be a bad sending unit?