Aftermarket grill cause higher temps?
 

Anyone who has installed grills ever noticed a higher engine temperature. I recently installed some stainless steel radiator grills from a well known company and it seems my oil temperature is a bit higher now. I wonder if the grills restrict the air flow to the extent one would see higher engine temperatures? Any of you grill guys or engineers have an observation?

Subscribed! I have been contemplating in buying some grills for my 997.2.

Do you have any real temp numbers? You can't really go by what the in dash temp gage reads.

While the screens interfere to some extent with the air flow I doubt they interfere that much.

(Just a heads up: What might have happened is a large piece of paper might have gotten sucked up against a screen and blocked air flow to that radiator until you shut off the car and the fan stopped. This is risk with the finer screens.)

Has it gotten hotter where you live? A nice heat wave can have a big effect on how hot the engine runs and the temp gage needle car reach regions it has not reached for a while. And this looks like a big cooling system issue.

Also, check the radiator ducts are clear of trash.

Check the coolant level.

Be sure the both fans work even if the A/C is off.

Radiators are very clean. Coolant perfect. My oil temperature is not excessive (never above 220) in 90 degree weather and town type driving. On the road always 200 or maybe slightly higher. This data is from my gauge and I have no idea how accurate it really is. Hopefully more accurate than the water temperature gauge that only goes to 175 no matter what. It is just that I installed the grills and am noticing slightly higher temperatures than before installation. Maybe it is the weather. Made me wonder if there is a known air restriction problem. So many informed people out there so I thought I would ask. Thanks to all that respond.

How much higher is the oil temp after the addition of the mesh grills? I installed grills during the install of my 3rd rad. My oil temp cooled by ~20*F afterwards. With the 3rd rad... the negative effects of the grills were negligible. The grills, however, do protect the radiators from damage and keep debris from clogging them up which would also diminish how effectively the engine oil cools off.

Why do you say that? I've heard it a few times on this board but have never heard a decent explanation of why. Seems like a strange place for Porsche to skimp.

That said, my car had an aftermarket grill already when I bought it, and the temp gauge seems to behave consistently with other cars. The particular grille I have is pretty fine wires with large air holes, I don't imagine it would impede airflow much unless something large got stuck to the front.

I have grills that I built and installed on my '09 with PDK and have seen no increase in oil temps. I also have the third radiator mod. I'm a real fan of the protective grills. Take a rock or other trash in a radiator and see quickly how high your temps go, plus the cost of a new radiator causing your blood pressure to also rise.

How do those with grills clean behind them to remove the inevitable accumulation of insects, debris, etc? We are very buggy in S. Florida.

In my case simple as I designed and built my grills. The outside grills are mounted behind the factory semi grills and attached by tie wraps. The middle grill is attached by screws to small "L" brackets I made and mounted to the opening in the bumper cover. It is easy therefore to remove the center grill and get your hand or vacuum in to clean the center as well as the outside radiators.
I've made probably 10 sets for friends and having the center radiator opening makes cleaning easier. For the 991 with no center opening just a blank black plastic panel it is harder. For that car you can carefully clip two tie wraps on each of the outside grills and snake a vacuum hose in.


Cost of materials for a set of grills is less than $10 ( that's for a car with three radiators) and it takes me about three hours to shape and fit and install them once I have the pattern made. Because we are dealing with plastic bumper covers each car is slightly different.

If you have the front bumper cover off for other work you could mount the grills from the inside but removing them for cleaning would be a problem. Hope this helps.

Despite having temperature markings on them, the water temperature gauge on most modern vehicles are actually programmed with a logic board on a log scale and do not fluctuate with real coolant temperature. They have modes to indicate cold, normal and overheat. Once the gauge is in the normal position, it will take a larger increase in temp before the gauge will start to creep up. Some drivers obsess over changes in vehicle temperature, though it is operating within a "normal" range. Unless there is something wrong with the vehicle, it is likely that the gauge needle will not move from a fixed position so as to not alarm the driver.

Are you speaking about water temp, oil temp, or both?

As another data point, I have screens, only two radiators, and I have noticed only a slightly higher oil temp when DE'ing or time trialing (sports plus). No change in water temp, all according to factcory installed gauges. On normal street driving, no oil or water temp deviations from "pre-screen" state.

I have the ZUNSport Grilles and there has been no noticeable difference in temperature in normal driving. With or without grilles, temp raises with aggressive driving in Sport+

The gage is dampened. Engine coolant temps ( along with oil pressure ) is all over the map, so to speak. If you could see the real numbers you'd probably be bugging the dealer daily.

The gage is really for show. By way of example I drove in 116F heat (southern AZ) in my 02 Boxster. The temp gage needle climbed to levels I've never seen before. The coolant temp (checked with an OBD scan tool) reached 226F and stayed there. Intake air temp was 135F and the engine compartment fan was on all the time. Back home worried about the extreme temperatures and readings I spoke to my SM and he contacted the factory. The word back was if no warning lights were on no overheating took place and there was no damage or any sign of cooling system issues from the extreme temperatures encountered.