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shoot4boge · 09-29-2016, 10:20 PM

We have a 2012 Thor Serrano 31X. This is my 2nd Class A and first Diesel engine. It is a FRED with 29,000 miles purchased used. While traveling today on our first outing with it the Check engine light kept coming on and peeping after about 2 hours of driving. It was very hot out here in Calif. today and we were in lots of stop and go traffic plus some hil climbing. I called the resale dealer we purchased it from and he said pull off the road and let it cool down which I already had done. I was able to drive a couple of hours and the system went off again!. It appeared to happen when we were doing any incline driving. I would pull off the road give it 10 minutes then start my travels again with the same thing happening again. I am really upset and feel I didn't do my do dillegence checking this rig out well enough. The temp gage never went past normal setting except for one hill climb when it went from the middle way over to the 3/4 line! Again the seller tells me it will be ok! What do I do??? Please offer some suggestions!! Perhaps a dirty air filter?

Skip426 · 09-29-2016, 10:48 PM

Welcome to iRV2.

Sorry you're here with problems .

Without pulling codes from the engine control module , everything will be a guess.
First look for the coolant level in the overflow , even marginally low it can trigger an alarm and light; and sloshing around on hills could be enough to set off the alarm.
Look around for an, air filter state indicator; clear plastic about 2" high, green re-set button on top; on the engine intake plumbing , between the filter housing and the intake , if the filter isn't passing enough air the indicator will show red; but you should have other indicators too , low power and black smoke out the exhaust under load.

edgray · 09-30-2016, 07:00 AM

I believe you have a Workhorse chassis with the Maxxforce 7 engine. There should be a fan behind the radiator which had a thermal clutch to engage the fan to pull more air thru the radiator which should produce a noticeable roar. If you are not hearing the roar periodically as the engine heats up, then I would suggest you have a competent mechanic look into the fan clutch. There should be rubber "air dams" around the engine compartment that are intended to force more air to go thru the radiator rather than escaping around it, so look at that also, but the fan clutch is critical and could allow the symptoms you described if not activating the fan in a timely fashion. Good luck.

DD788Snipe · 10-01-2016, 10:18 AM

edgray I don't believe WCC made a FRED chassis. Only Freightliner did with the 6.7 Cummins engine. To the OP. Purchase a digital infared laser thermometer. They're cheap at Harbor Freight tools. Go test drive a your rig. When the light comes on check the temp at the engine water coolant return hose. If it shows between 185°-225° you have a bad sensor. If the temp is higher take it to a Cummins repair shop. Could be a number of things. Could just need a coolant flush and new thermostat but they will be able to diagnose your problem.

Gary RVRoamer · 10-01-2016, 04:23 PM

You are both right and wrong, DD788. "FRED" is a trademark of Freightliner Custom Chassis and refers only to their front diesel, but Workhorse did make a chassis with a front diesel as Ed describes, and that's what the Thor Serrano uses. So it is incorrect to call it a "FRED", but it is a front diesel chassis.

In any case, shootforboge needs to consult his Workhorse chassis manual for the meaning of a Check light and beep. And maybe get codes read too. I could make a pretty shrewd guess for a Freightliner, but not Workhorse.

edgray · 10-01-2016, 06:54 PM

Quote:

Originally Posted by DD788Snipe

edgray I don't believe WCC made a FRED chassis. Only Freightliner did with the 6.7 Cummins engine. To the OP. Purchase a digital infared laser thermometer. They're cheap at Harbor Freight tools. Go test drive a your rig. When the light comes on check the temp at the engine water coolant return hose. If it shows between 185°-225° you have a bad sensor. If the temp is higher take it to a Cummins repair shop. Could be a number of things. Could just need a coolant flush and new thermostat but they will be able to diagnose your problem.

You are mistaken. In fact, WCC introduced the W series in several different GVWR and used Maxxforce Diesel engines in all of them. They just added " D" after the numerals to indicate they were not the 8.1L gasser chassis. They did not call them "FRED" because that moniker was associated with FCCC products, but the WCC products DID have diesel motors in the front. The OP's coach is just ONE of the products built on front engine diesel chassis made by WCC.

In case you didn't know, WCC also made traditional DP chassis for several years. the first models had Cummins ISC motors and later they had Cat C-7 or perhaps a C-9.