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Ah this is my favorite one yet from this series. These were my old stomping grounds, from my Montana days (see my avatar). These roads were made for the 928! I never had overheating problems, with the one I moved out there with (an 86.5) or the one I got when I lived there (Blumaxx, a 78). The Beartooth Highway was epic, a bunch of us took a trip over it, and both of my 928's were on it. Me in Blumaxx and my buddy in my old 86.5 that he bought from me, plus a couple of other 928's and a Corvette. The only car that had trouble was the Corvette - we had to do road repair/tech session at 11,000 feet on it - at the top of the mountain! (Stan would be proud - we got it running). The Going to the Sun Road has to be seen to really appreciate it. I think these are two of the best roads in the US ('ve driven a lot of the great roads too, from coast to coast). Anyway, this is a great series. If you haven't seen the first two, it is worth your while to find them and watch. Here we are on top of the Beartooth:
The Corvette:
The aren't kidding that the road over Bear Tooth Pass is one of the best drivers roads in America. DO NOT miss it if you are anywhere in a 500 mile radius during the time of year when it is open.
I was curious about the cooling issues as well. I literally never run hot, in stop-and-go in the middle of a South Florida summer. But the altitude thing is not something I encounter down here, obviously.
Only time I experienced cooling issues with everything working in my 81 (similar enough to their 84) was with the factory electric condenser fan and metal engine fan.
A big SPAL replacing the original electric fan fixed that issue.
I have a plastic engine fan on my 85 and it runs cooler than my 81 ever did with the original hardware. With the extra 70 HP the later engine pumps out more heat so I think that could be his issue, either that or a failing fan clutch.
Either way, it was an interesting episode to watch the trials and tribulations of taking an old car on a road trip. Something the 928 excels at wonderfully.
cooling issues > my euro would always run warm in traffic UNTIL I dumped the heavy and complex and inefficient factory fan and replaced with an effective electric puller mounted on the radiator. I think a belly pan would make a big difference also, which I don't have.
After my recent TB/WP I decided to keep the front plastic covers OFF, they act like a coat and hold a LOT of heat in the engine. Looks better w/o too.
Ah this is my favorite one yet from this series. These were my old stomping grounds, from my Montana days (see my avatar). These roads were made for the 928! I never had overheating problems, with the one I moved out there with (an 86.5) or the one I got when I lived there (Blumaxx, a 78). The Beartooth Highway was epic, a bunch of us took a trip over it, and both of my 928's were on it. Me in Blumaxx and my buddy in my old 86.5 that he bought from me, plus a couple of other 928's and a Corvette. The only car that had trouble was the Corvette - we had to do road repair/tech session at 11,000 feet on it - at the top of the mountain! (Stan would be proud - we got it running). The Going to the Sun Road has to be seen to really appreciate it. I think these are two of the best roads in the US ('ve driven a lot of the great roads too, from coast to coast). Anyway, this is a great series. If you haven't seen the first two, it is worth your while to find them and watch. Here we are on top of the Beartooth:
The Corvette:
Any guesses as to why they were both running hot at altitude?
Going leisurely up, down, around on even gentle mountain roads requires two three or more times the 20-bhp needed to cruise at a steady 60 mph.
Most of that heat goes into the coolant.
Originally Posted by ammonman
My vote is lean mixture or incorrect ignition timing.
My vote: Reservoir cap is dead and holding zero PSI instead of 14-ish.
Every single 928 that has rolled into the shop this year had a *bad* cap.
Now, don’t everybody go out a buy a new cap and slap it in though. Guess what happens when your cooling system that’s run at a few PSI for years starts running at 14?
Last edited by worf928; 12-27-2022 at 03:57 PM.
Reason: good->bad (needed more coffee)
Having spent a good bit of time driving in the Rockies as well, I add +1 to Worf's vote for overheating. And to Ed's vote for Beartooth as one of the best roads in the US to drive (but I last traversed it over 40 years ago driving a 3 liter MB turbo diesel sedan with the wife and 2 kids aboard - wishing I'd been at the wheel of my '73 BMW 3.0 CS)..
We did prepare the car for the road trip. The guys are super nice. Actually, the guy with the 300ZX lives about two blocks away from me and I have never met him until the other night when I picked some parts up from him. We didn't go through the whole car, but we did service a number of things. After he returned from the drive, we found that the vacuum routing was incorrect and the timing was off. The car ran much better after the adjustments. Much more powerful and it ran cooler as well. Altitude certainly plays a huge role. His AC blew super cold, however with the addition of a current technologies parallel flow condenser. The car runs super. Although many people don't service the 928s as much any longer, we still find a few examples in our shop at any one time. We have serviced so many over the years that we thought we fixed them all out this way, but every once in a while we see another that needs some help. We still build the crossovers and complete exhaust although we do sell fewer of them and only have Roger as a reseller any longer. Thanks to all Rennlisters for the business over the years. We certainly appreciate it and NEVER take it for granted. One day we might break a couple of really unique examples out of the stable for Everyday Drivers to take for a spin. I want to do Yellowstone in the 928 one of these years, but alas I have way too many kids for that. Guess I'm stuck with the turbo diesel suburban and a chase car. LOOLOLOLOLOLO. Happy New Year.
12-23-2022, 12:00 PM
The guys from Everyday Driver are back on the road in the 928 and 300zx.
