Question :

How do you keep your 912 cool during summer heat and long drives?  New! 912 Registry Members can share technical information, add technical information, and access quality, up to date technical information on our 912 Wiki.

From: Bruce L. HERRINGTON;  I tried the various tips with insignificant results. The shield between the heater boxes to protect the oil pump from direct radiation from the muffler made no noticable difference. The insulation pading in the engine compartment might have helped. I removed the heater boxes completely and some days I was convinced that it had helped, others I was not so sure.
Then I met a guy who was making GT grills for 914s. The have twice the area of the stock, and he said that there was a market for such things because in the SoCal climate the 914 needs all the air it can get. Considering that comment, I removed the plastic rain shield under the 912 engine grill.
No doubt about it, removing the rain shield helped. The temp on my normal evening commute dropped by about onehalf the width of the upper white zone on the temp gage. Feeling that I was on to something, I built an 'air scoop' the full width of the hood opening, and 4 inches wide.  That dropped the temp by an additional full width of the white zone.
Where I used to 'pussyfoot' home, slowing on the upgrades and cruizing at 60ish with the needle just touching the white zone, now I can pass other cars going up those hills, cruize at well over 60, and keep the needle well clear of the white zone.
The air scoop approach works so well, I might even make up some extra scoops, if anyone else would be interested for next summer.
Bruce

From: D. Reynolds; Keeping foreign objects from being ingested by the fan is the preemptive way of keeping the cooling system healthy. Two sources of foreign objects:
1. From inside engine bay
-Deteriorating sound-proofing material as already mentioned by others.
-Any loose nuts/washers/wire insulations/etc. that have escape attention for too long
2. From outside the engine bay
-A rubber seal runs along the entire perimeter of the sheet metal engine  tray. Check that it hasn't become twisted out of shape over time due to engine twisting. The area just in front of the fan intake is
important for keeping road debris out of the fan.
-Forward of the cross-member that supports the shocks is a seal that is made from a rubber tube filled with foam. The gap filled by this seal is also in a location that would allow road debris to enter the area in front of the fan intake.
Doug Reynolds
12804548

From: William Todd; You'd previously asked about cooling for summer in a 912. I just pulled my engine and am putting in new Deves piston rings and all new seals on the "top" end. I removed the doghouse, and was a little surprised to find my oil cooler had been leaking a bit. Not enough to really do a big, noticeable loss of oil, but hidden in all the "normal usage."
The upshot was, that the grime and oil slung into the cooler by the fan packed an estimated 25% of the total fin area on the cooler! I have it ready to cold tank tomorrow, and flush out internally, plus removing
all that accumulated "yuck" in the fins. There are a few fins that I straightened out to permit a free flow of air too.
Check out the condition of the fan by using a mirror and a flashlight. It should not be coated with oil and grime. Keep the fan clean, and it will pack more air into the doghouse. I am also washing/wiping out the doghouse, shrouding, etc when I re-install. Any dust, grime, etc that builds up disturbs both the volume and flow of the air sucked in by the fan.
This will help my already cool running engine a bunch, I'm sure. I'm an ex-aircraft/helicopter mechanic with about 30 years of air cooled engine building, including a bunch of VW's & Porsches. The secret of long life in any air cooled engine, be it aircraft, helicopter Porsche, VW or others, is a good supply of cool, clean fresh oil!!
An insider secret is to paint a VERY LIGHT coat of black high temp engine enamel on the cooler. Black bodies emit a far higher amount of radiation and are able to get rid of heat quicker, ask any physist!  If you believe the TV ad that: "Nothin' does it like 7-UP," you've been had! Nothin' does it like cool, clean fresh oil!
Keep the 912 Faith,
Bill

From: DAVID LOVATO; The 912 site gets better and better! What a super job, and much appreciated by this Porsche nut!
Hot days- hmmm.. try the Autostrada North from Rome to Bologna, or the roads in Apuglia in August...we're talking HOT!
Keeping a 912E cool in hot weather is a a double challenge. Firstly the car is rarely equipped with A/C, and if it does have the power sapping extra compressor/belt arrangement is probably even more likely to suffer rapid motor warmup as well as half-hearted interior cooling!! For those brave enough, I have seen original 912E A/C systems for sale occasionally although I wonder why they were removed from the cars if they worked even marginally well!! So, you leave all the windows open, crank back the sunroof, and if you have the optional opening rear quarter lights- you're in luck! The only thing that's cool is the way the car looks!!
The motor on mine has always tended to run in the top third of the 'idiot' temp guage on warm days, running a little higher if the ambient temp got above 90 degrees F. Having run my four-banger several thousands of miles at speeds above the U.S. norms (but normal on Autostrada and Autobahn- 130- 170kph) I was especially concerned about overheating. Several things are widely suggested as partial fixes: Do away with the thermal reactors and install by-pass tubes ASAP. The TR's are commonly termed 'head cookers' by the many I've consulted and contribute a lot of un-needed exhaust temp heat. Oil cooling (by additional external cooler) seems to be the next big consideration, more often applied to 914's- but mostly in conjunction with a big sump (more oil!), HD oil pump (careful how you install) and
oversize pressure relief valves. Next, the head temp sensor is v. important (apparently). Bosch advertises sensors occasionally as part of the 'hot running' problem, I believe.
But the best way to do a high-speed long distance run in warm temperatures is to seek RAIN !! It works wonders on keeping the hard worked boxer 2-Litre at mid-range temp, even if the next concern is whether or not your tires are up to the job of displacing all that water!!

R/Dave Lovato 9126000496 (Enjoying the back roads of TN and MS and just back from a 1000+ mile road run to Atlanta and back- and yes...I found rain!!)

From: Bruce L. HERRINGTON;  Has anyone had any real experience with running without the heater boxes in the summer. 356 Registry had a discussion on this some months ago, but it was mostly theoretical and mostly of the if- Porsche- put- it- there- it- must- be- right kind of thinking. My 68 912 is tired, 312K miles, and does run hot (gage and sender freshly calibrated by Palo Alto Speedo), even after careful cleaning of the engine and oil cooler. I'm sure pistons/barrels and a valve job would help, but removing the heater boxes would be easier and cheaper. Anyone know if it's worth the effort?

From: Patrick Van Asbroeck; The previous owner mentioned the engine was overheating occasionaly. To improve cooling I did the following:
-checked the ignition timing, now at 3 degrees BTDC
-cleaned the oil cooler fins, underside of the engine casings, inside of the air covers and wire mesh air inlet. They were all covered with sticky dirt.
-put new rubber covers of the sparkplugs.
The oil temperature dash meter wasn't indicating much heat even with a hot engine. I checked the oil temperature directly after several rides with a handheld electronic temperature gauge and found it always to be within the 80-90 degrees C. I removed the heat sensor and heated it in a gas flame to about 100 degrees C with all the original wiring still in place + an earth between chassis and the sensor housing. Then the dash meter works fine!  Patrick

From: Andy 912 Keller; Dear 912 Friends:Re: Cooling
Passenger compartment:
Porsche suffered a severe design regression after the early (I believe designated O- series) cars -- the deletion of opening quarter windows. "Plugger" air conditioning.... In my 1967's compartment that can
house a  gas heater, I installed a blower that feeds the dash outlets. This does not   add much to hot weather comfort but it does assist de-misting. About the cowl vent, I noticed while slowly adjusting the angle of the sun visors' that the sun visor set an a certain angle can help deflect some moving air to the
occupants' faces'. My car is white so that helps reduce the effect of radiant heat; so much that the luggage compartment will stay cool all day long in a midsummer day.
Engine Cooling:
My engine is mostly stock except for ISS big bore pistons and (cast iron) cylinders (displacement of about 1719 ml). When I installed them about 20 years ago I took the precaution of removing molding flash and protrusions due to mold shift. Also I gave the fins a thin coat of high temp black paint to
assist heat dissipation. Only after about 15 minutes of vintage race laps does the engine get so hot that I watch the temp gauge. While driving the car at touring speeds it is hard to get up to temp (above the boiling point of water, about 202 F here) even at ambient 95 F at 5000 ft altitude.
As a precaution and for added protection I use synthetic oil, whatever brand is on sale for < $3/qt.
Over 15 years of on-and-off vintage racing and several years of high-speed solo events (mostly PCA driver education) and the engine has not been apart. Not fast, but reliably and not finicky.
Buckle up and enjoy,
Andy 912 Keller
Longmont

From: LJ Carlin;  I have a 1968 912, i just recently picked up a rain shield at the Hershey swap meet. I paid $20.00, what a steal. Since then I've noticed that my running temp is reached much faster than it had, I'm not worried because my temp gauge stays right at above the soild block on the left side of the gauge. I Think I FOUND THE TRICK. Go to ANY car place, Pep Boys, Auto Trac, Big A, They have this sound barrier mat, (heat sheild), It's shiny on side with a rag back. With all the engine shields in place. (shields to keep the exhaust heat below), Lay this material shiny side down over the whole engine compartment floor........I Know, I Know This seems like you are traping the  hot air in but, The material reflexs the hottnest(lack of better words) back  down below where it belongs, allowing the fan to draw in the cooler air from to top of the vehicle. I came up with the idea this winter. I was trying to come up with a way to heat up my heater boxes faster, it worked....but now its summer I thought about removing them,(mats), but make engine compartment is still very cool. Like I said my car runs at just over the solid block on left of the gauge.... COOL.

From: Larry Bevins; Fellow 912ers,
According to the drivers manual a 912 will run its coolest when:
1. The ignition timing is correct (if the timing is off the engine will run hot).
2. The pulley belt is properly tensioned (a slipping belt will cause the engine to heat).
On top of that I'd have to say that there are several other ways to make sure that your car stays cool on long hot trips:
1. Remember that while a Porsche engine is "air cooled"... it is also oil cooled. In hot weather be sure that the oil level is at a healthy level... and also that you are using the proper weight of oil for summer like temperatures (I recommend 50 weight oil... 10/50 if your'e using a multi-weight oil).
2. Also don't forget that your engine has various shrouds that are meant to move air around and cool the engine... make sure that these shrouds are installed properly... in some cases they may even be missing and will need to be replaced.
3. Then there's common sense... drive during cooler times of the day (it works for lizards and jack rabbits, don't take the rpms up too high, park in the shade, etc.
If all else fails try what Team Corvette did when they took a shot at LeMans in the 1960s... pack the engine compartment with ice... by the way, it didn't work.
Vaarrooom,
Larry Bevins

From: NO911NV;  Just changed to synthetic(Mobil One) for the transaxle and engine. If it won't run cool, than the oil better be good. I use Mobil One in my Mustang race car, oil temps to 290 degrees, and have had great luck with it. This will be my first summer with the car, so we'll see.

From: Barrie, Robert;  I don't know how to stay cool, but can someone please tell me what the correct temperature sender is for a 69 912 (part no if poss), where should the needle be most of the time and what is the calibration of the gauge - how hot is hot? thanks, Robert.

From: brian reynolds; Rick, never had my car on long trip. Seems to run cool in normal driving conditions.keep up the great web site. brian

From: NONI80; I have a 912E that always runs hot. The engine was rebuilt but it still has the same problem. I checked oil cooler, engine pan seal, stat and flaps. All are working. Anyone have any suggestions.

From: Tor-Staale "I-902" Hansen; I have mounted a external oil cooler just underneeth the grillpanell. The oil heat meter points bown all the time. I thought the meter was broken, but afther a check the meter was right and that shows that my engine is cooled properly. Best from Norway Tor-Staale "I-902" Hansen

From: Jerry Allston;  Living in Phoenix for 25 years, my 68 912 has seen plenty of heat. To restate some of the previous entries: If you have the old foam type sound deadening in the engine compartment, it breaks down, gets sucked in by the fan and jammed into the oil cooler. Play with your timing, a degree or two can make a noticeable difference. I now run Castrol 5-W50 Syntec oil, but before that I would run straight 40W during the summer. Finally I had C&E Engineering in Calif modify the oil pump outlet and timing cover to pull the oil to an external cooler. That is the best answer. The addition of the 911 type gauge that indicates temperature and not just range is a much better indicator of what's really happening. I run the freeway now at about 70 mph (4 speed) 100+ degrees outside and oil temp of about 210 degrees. Regards, Jerry

From: Mark Price;  Is it possible to get a 912E to run cool without resorting to a 911 type fan system? I think not. I have added an auxillary oil cooler back in the rear wheel well and it helps somewhat. I also think it pays to keep as much oil, grease and road crud off  the engine also. Mark Price

From: rodger stewart; To make it through Colorado's long, hot (dry) summers I use my 280 air conditioning -- two windows down and 80 miles an hour. Rodger Stewart, Franktown, Colorado

From: Larry Grossman;  I found that running a good synthetic oil helps, I was using Red Line , but switched to castrol, seems to work good , even if it gets a little hot I think the oil can take it,unlike regular oils.....................Larry

From: Greg Bryan;  Keeping it Cool ...If your 912 is in most respects normal and the oil temp gauge seems to be running on the hot side, the problem could be that the fins under the sheet metal are choked with debris. Along with the enormous amount of air that the cooling fan draws into the cooling system, a lot of dirt, dust, leaves, bugs, paper, small birds - you name it - are brought in with it. The only effective way to clean it is to remove the engine and all of the sheet metal and clean all of the stuff out. I've seen oil coolers that are almost completely blocked with dirt. If you have even the smallest oil leak, especially in the oil cooler area, that guarantees that the dust will stick to the engine and not pass through. And, if your engine compartment insulation is starting to deteriorate, it will get sucked into the fan and impede the flow of air. Don't ever paint the heads or cylinder barrels - that inhibits their ability to shed heat. Sounds silly, but I've seen it done. If your carbs are jetted too lean or if your timing is too far advanced, that can cause engine overheating. Also, don't overlook the obvious - the fan belt needs to be properly adjusted and not too worn on the contact surfaces - you shouldn't be able to turn the generator by grabbing the pulley when the belt is in place. Also sounds silly, but it's not that uncommon. Finally, make sure the engine compartment seal on the body is making good contact with the engine sheet metal. You want all of the cooling air to come through the air grill in the lid, not to be preheated by being drawn over the hot exhaust system before it enters the engine air intake.  These are a few of the things I've come across in 25 years of fooling around with these cars ...

From: Matthew Guerrero;  I have a 912E and have often wondered how to keep my E cool. One idea that I had was to put a temporary blocking plate in front of the air passage ways for the heater boxes. It seems that if the air passage ways were blocked, more air would be forced over the heads and cylinders. However, I don't know if there is an airflow requirement for the heaterboxes. Just an idea. My other idea is to move to Alaska. Matthew Guerrero

From: Will Ricketts;  The question about cooling is a really good one. my 68 performs very well in all conditions except the extreme heat here in Texas. My oil temperature runs just below redline when cruising at 4000 rpm in 5th gear. I wish there was a readily available fix for cooling the oil better, perhaps external coolers like the 911 has, or what??? anyone with a solution? Will Ricketts, '68 5-spd coupe

Techtip: Cool your engine by replacing an often overlooked engine compartment seal!

New! 912 Registry Members can share technical information, add technical information, and access quality, up to date technical information on our 912 Wiki.