Automotive/Engine Overheating

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Expert: - 8/22/2008


Question
I recently had the coolant changed by the Pontiac/GM dealer. The engine is overheating on steep hills. The car is a 2002 Pontiac GP, V6, 3.8 engine, 101,000 miles. I have beentold that the GM coolant may be the problem ?

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Answer
Coolant generally is a mix (50:50 or higher) of glycol antifreeze, water (demineralised, in higher-specification antifreezes) and combined rust inhibitor and water pump lubricant.  I have heard nothing about "GM coolant problems" and would be inclined to doubt that there would be any problems with reputable name-brand base ethylene glycol.

New coolant is only one part of good cooling system service, however.  Systems should be cleaned and flushed each time coolant is changed, and the thermostat should be changed - these do not last forever.  (I would be surprised if the dealer did not do all this, as it is standard practice.)

Other problems could include a failing fan clutch (if used in this car), or a defect in either the fan thermostat or the fan circuit if an electric radiator fan is used.

Finally, how clean are the air passages through the radiator fins?  Any season's collection of pollen or build-up of bugs could be reducing the heat transfer efficiency of your radiator (correctly, air-to-water heat exchanger).  This can be fairly easy to clean, using a soft car-wash brush and a gentle stream of water through the fins from back (engine-side) to front, that is, in the reverse direction from that in which the air normally flows.  Just DO THIS WITH CARE!  Fins are readily damaged or bent closed by too-aggressive cleaning action or excess water pressure - do NOT use a pressure washer!

Good luck ... EGK

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Ernest (Ernie) Kenward

Expertise

The challenges I most enjoy are thoughtful technical questions of a trouble-shooting nature in both electrical, power electronic and mechanical systems, mainly automotive but also machine control and small-machine PLC applications. Please note, however, that I am NOT a walking shop manual! I DO, however, make it a point to have those manuals and other service literature for those vehicles I DO own, and highly recommend that anyone serious about maintenance or modification of their vehicles do the same; MOST of your answers WILL be found there. For that matter, I do NOT go out of my way to acquire shop manuals for any vehicle I do NOT own! That being the case, any general query to me along the lines of "What is the meaning of this code read from the ECU of my 2015 XYZ?" or "Where is the fuse for the windshield washer pump found?" (try your car's electrical distribution panel for a start!) will not go far. What I do offer is a pretty good collection of literature, insights and hands-on experience with 1950s to 1980's Ford products (plus a developing database of information and practice with the Mercedes diesel cars), along with an engineering perspective and the ability to design and implement custom control, electrical and mechanical subsystems for vehicles. For that reason, I am happy to make my thoughts and efforts available to those who are of like mind and/or are seriously making a point of learning about their vehicles. Use the Opportunity to Learn!

Experience

A key skill in my work and hobby pursuits both is STRATEGIC TROUBLESHOOTING. I am a senior instructor in Electrical Engineering Technology at a leading Canadian polytechnic, my areas being Electrical Power and Industrial Control, electrical and electronics design and manufacturing, and AutoCAD and related CAD/CAE software - plus equipment problem-solving and new equipment design and prototyping. Hobby-wise, I have 30-plus years of experience in auto restoration, mostly in electrical and mechanical systems. Ongoing projects include a 1959 Edsel Corsair, my 1978 Ford E250 class-B motorhome conversion, and the care and upkeep of my Mercedes 300CD. My vehicles become engineering test beds for electrical and mechanical upgrades as ideas present themselves. This includes the design and production of circuit boards to restore or enhance features for which no OEM replacement parts are obtainable, or where better specifications or reliability can be had via newer concepts. Regarding the E250 RV conversion, I designed and continue to revise a custom power distribution system, managed by a Programmable Controller (PLC); this has made most revisions as easy as uploading new firmware as I develop it. The "mini" PLC is a powerful device for custom automotive control systems. One good example (there are many) would be the Moeller "Easy Relay"; these offer a wealth of control, monitoring and variable-and-status display options for such projects. A good example project which has worked well is that one for my RV noted above, which has been on the job - revised in firmware only - for a decade now. It is a load management and charging control system to avoid the sulfation-induced early failure that often befalls deep-cycle batteries used in RV power applications. The battery installed in 2003 lasted long enough to more tnan pay for the PLC that contributed to its longer life ... and the PLC will be there for the next battery as well!

Organizations
IEEE - senior member ... past WCC Student Activities; SME - senior member ... past chair, greater Vancouver chapter chair 318; Edsel Owners' Club - have served in various capacities on chapter executive during seventies; have been Power and Driveline resource on the Edsel Owners' Club "E-team" for more than a decade.

Education/Credentials
Graduate of UBC

Awards and Honors
Certificates of appreciation from IEEE and SME for work in student and chapter activities

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