Heating Up

A cautionary tale of underhood heat.


THIS memo showed up in my e-mail the other day. It came to me indirectly from QFix Truck Service, an independent repair shop chain with facilities in Kentucky and Indiana.

After I read it, I quickly called the gentleman who wrote it, Bill Crenshaw, and asked if I could reprint it here in my column, and he and his company's management agreed. Here is the memo that Bill circulated:

TO: ALL MANAGERS & TECHNICIANS FROM: BILL CRENSHAW RE: EXCESSIVE ENGINE HEAT

We have been reading & hearing at meetings for the past couple years about excessive engine heat under hoods of trucks caused by all the emission equipment twin turbos etc. We haven't seen much of these problems in our shops yet but some of the trucks are now getting a couple years old & they are showing up in our shops with a problem. Last Fri I was working in LJ & we encountered one of them which we did not realize what was problem & we did not handle it as good as we could have.

I am writing this memo just to let everyone know to be on the lookout for these problems.

Truck came into shop with alternator problem no big deal we replace alternators everyday. The truck was a 2004 Pete with a CAT C15 engine. When we got truck in shop & raised hood we found the serpentine belt that goes around everything on the CAT to be broken. OK we checked alternator pulley would not turn bearing in alternator was locked up so we removed alternator & checked idler pulley bearing in it was also locked idler pulley would not turn so we ordered new idler pulley.

Installed new idler pulley, alternator & belt. Load tested batteries found one bad battery replaced it customer would not go for to replace all 3 batteries. Engine would not start would not crank over acted just like batteries were dead so we charged batteries for ½ hr no results so we charged for another hour still would not start. Load tested starter it checked out OK was only drawing 750 amps but would not crank engine over acted like batteries were low. So we installed 2 more new batteries this made no difference so we removed 2 batteries & reinstalled old ones which tested OK. Also in this process we had checked & cleaned all connections & cables everything was ok but engine would not turn over. We decided starter must be problem customer would not replace starter so we pull started truck soon as engine turned over broke belt. Brought truck back in shut off & restarted fine starter cranked engine over just like it is supposed to. What we then discovered was the fan hub bearings were locked up fan hub would not turn & this was putting such a load on starter it would not turn engine over. Replaced fan hub everything was OK.

Analyze the total situation alternator bearings were locked up, idler pulley bearings were locked up, fan hub bearings were locked up. They all have sealed bearings so what happened was due to excessive engine heat grease in bearings had gotten hot & ran out of bearings therefore they all locked up.

So when we get truck in with one of these similar problems we need to check everything associated & repair all at one time & not just one problem at a time as it arises. This will bring in more revenue into your shop as well as do a better repair job for your customer & also make our organization appear to the customer as being more professional & our technicians knowing what they are doing. Because the customers have been reading the same material we have & they know this is a problem with newer trucks.

To me, that last phrase is key. Yes, customers have been reading the same material, here in Fleet Maintenance Magazine, in the Technology & Maintenance Council's publications, and in other publications. Now, of course, the case described above by Mr. Crenshaw does not involve a 2007 model year diesel engine, but it does illustrate the damaging effects of underhood heat.

I think the important point here is that Mr. Crenshaw and the management of his company thought this particular episode was important enough that it warranted this memo, to be circulated to other service directors and their technicians.

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