Engine overheating? Or bad temp gauge?

[JohnKimball]

Merry Christmas everyone,

I purchased my first RV, a 2005 Fleetwood Flair 34F on a workhorse chassis over the summer. Everything ran beautifully the first couple of months, but recently the cooling system hasn't been able to maintain its previously normal temperature, which was just below the "halfway" mark on the gauge. The gauge has been, for the most part, rising steadily as before, but now it comes to rest about 3/4 of the way up towards the overheating zone, and sometimes even stops one tick mark from the overheating zone. However, once or twice when starting the engine after sitting for a day or more, the gauge would jump straight to the halfway point immediately (within a second), and then continue its journey higher. This makes me think it may be an issue with the temp gauge. But either way, it's taking all the fun out of driving my new RV, constantly watching and worrying about the engine temperature. Has anybody had similar experiences with the 8.1L workhorse?

I checked the engine coolant reserve (while parked level) and it shows just below the full cold line with the engine having sat for a few hours. I opened the radiator cap to top it off just in case, and the coolant level literally sat right at the opening of the filler cap, so I couldn't have possibly added more if I wanted to. Am I doing something wrong there?

Any thoughts or advice on this would be much appreciated. Thanks in advance.

[Arch Hoagland]

UltraGauge OBDII Scan tool & Information Center

You could get one of these and know the exact temperature along with lots of other information.

I suspect you may have a bad gauge.

[JFreitas]

It could be your radiator cap or thermostat. Mine was over heating I changed the radiator cap and added coolant all is well now. I also suggest that you get a scan gage.

[ahicks]

Until you prove otherwise, it's generally a pretty god idea to assume it's overheating. Guessing on gauges and sending units and associated wiring while the engine is cooking itself is not a real good plan.

Start with the basics, like coolant level. If it's beyond your skill level to do the diagnostics, don't guess. Get it in to somebody that can handle it for you.

[TeJay]

A few simple things have been mentioned. I really like the little hand held infrared temperature sensing gauges. All you have to do is point and shoot to get the temps. It's great to verify temps if you have questions.

As suggested change the cap. It's very important that the cap work to raise the boiling point of the coolant. They don't often go bad but when they do they can cause problems.

After you change the cap try a run and using the infrared gauge check some temps to verify if you are actually getting to hot. Once you verify the situation you can take the next step (s) if needed.

TeJay

[twinboat]

Without a chart of where to check temps and baseline readings to compare, I don`t think an infrered gauge is going to help most R/V owners.
He doesn`t even mention if there are numbers on his gauge, making me think it`s just a colored line, with red being bad.

Someone else suggested taking it to a trusted shop. I think that is a better course of action, in this case.

[Dmorgan6375]

I agree, take it to a shop to confer on the "Actual" temp. Could be just a bad sending unit and or a little low on coolant. Just a side note, most of these Gas motors run around 195 to 201 degrees any way. And yes a bad cap could lower the boiling temp to low. Everyone who has an RV that is motor driven either gas or diesel should have a scan tool on board, use it two times and it's paid for itself.

[Ron & Dee]

Originally Posted by JohnKimball

Merry Christmas everyone,

However, once or twice when starting the engine after sitting for a day or more, the gauge would jump straight to the halfway point immediately (within a second), and then continue its journey higher. This makes me think it may be an issue with the temp gauge. But either way, it's taking all the fun out of driving my new RV, constantly watching and worrying about the engine temperature.

Any thoughts or advice on this would be much appreciated. Thanks in advance.

I'm with you on the constant worry. I do the same when my gauge starts to move beyond it's normal position. To me your description of the gauge jumping straight to half way after just starting sounds like a faulty gauge. If you can't get that fixed, I would definitely purchase a Scan Gauge.

Ron

[edgray]

Originally Posted by JohnKimball

Merry Christmas everyone,

I purchased my first RV, a 2005 Fleetwood Flair 34F on a workhorse chassis over the summer. Everything ran beautifully the first couple of months, but recently the cooling system hasn't been able to maintain its previously normal temperature, which was just below the "halfway" mark on the gauge. The gauge has been, for the most part, rising steadily as before, but now it comes to rest about 3/4 of the way up towards the overheating zone, and sometimes even stops one tick mark from the overheating zone. However, once or twice when starting the engine after sitting for a day or more, the gauge would jump straight to the halfway point immediately (within a second), and then continue its journey higher. This makes me think it may be an issue with the temp gauge. But either way, it's taking all the fun out of driving my new RV, constantly watching and worrying about the engine temperature. Has anybody had similar experiences with the 8.1L workhorse?

I checked the engine coolant reserve (while parked level) and it shows just below the full cold line with the engine having sat for a few hours. I opened the radiator cap to top it off just in case, and the coolant level literally sat right at the opening of the filler cap, so I couldn't have possibly added more if I wanted to. Am I doing something wrong there?

Any thoughts or advice on this would be much appreciated. Thanks in advance.

Like the others, sounds like you may have a faulty gage and "most" code readers such as the SGII will read coolant temps off the OBDII port. I also suggest you read tip # 4 here:
http://www.irv2.com/forums/f22/workh...ons-71705.html

[sknight]

If it's jumping up halfway while stone cold then the sending unit/sensor is most likely faulty. It's internally shorted intermittently.

To replace it, you'll need to do a little detective work. In 2005 in the 2500/3500 trucks powered by the same engine the ECM used the signal from the sensor to activate the gauge in the factory cluster. But I don't know if workhorse used the factory gauge cluster. If not, there's probably another sending unit just for the cluster.

To replace it, you'll drain the coolant. Since you'll have the coolant out now is the very best time for some TLC. New thermostat, new belt(s), replace the fan clutch if equipped, new hoses and check the water pump. Sounds like a lot, and isn't necessary but is good peace of mind for not an extreme amount of money.

[M&EM]

My service manual shows one ECT sender. So if the sender is bad, a Scan gauge will get the same bad info.

[Clay L]

The Actia instrument panel gets it's info from the engine computer not directly from a sensor. The gauge is actually a glorified idiot light with three or maybe four indication positions.

You can run a diagnostic test on the IP. The instructions are in the service manual for the IP.
I attached the pdf file do you should be able to download it from this post attach it but if that doesn't work it can be downloaded HERE

As stated above a Scangauge will give you the temp the IP is seeing.

[TeJay]

To say that an infrared gauge won't help much for RV owners because you don't have any baseline temps is little confusing. Pull the dog house off and check all around the engine block checking for temps as it gradually get hot. Check the temps at the top of the radiator where the engine water comes in from the block. Check the temps coming out of the thermostat housing, that will be the opening temp of the thermostat and the engine coolant as it enter the radiator. You'll get some idea if it is actually overheating or if the temp gauge is not accurate. Once you have some info you can make a better educated guess.

It is absolutely perfectly accurate no but it's better than no idea at all.

TeJay

[M&EM]

I would pick the by pass port on the water pump for the most current temperature as it is always circulating block/head temps. regardless of thermostat status.