Porsche 944 - Coolant System Tutorial: Draining, Filling, & Venting 

Absolutely man! How’s your car been coming along?

4:46 4:46 4:46 4:46

Yeah, pretty interesting how sand is used during the casting process to create the cavities in the head, then later washed out, revealing the channels for the coolant to pass through.

Feel free if you’re close to central NC, I’ve got some free time. 😂 Glad the content is helping out and don’t forget, you’re saving $1,000s in labor costs.

@@NC944er southern KY so not a bad drive 👀

@@doubled334 🤣

The lines get a bit hard and inflexible with age, but you should be able to push them back under the sheet metal a bit. I did not need to do anything under the car. The cap is basically a lid with no center, so it twists off counter-clockwise. Try to loosen the cap and see if twisting/tilting the unit at another angle helps get a better leverage point on the hose.

Unfortunately I’ve already replaced the oil cooler seals on this car and the most I have from the job is a handful of pictures. There are a couple videos out there worth a look though. This one has some great info - ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-7T68yNp6Qrg.html

@@NC944er Thanks! I'll check it out.

You'll see a lot of different preferences out there on oil brand, but as far as weight, I use Castrol GTX 20w-50, which is good for warmer climates. If you live in a colder climate or will be starting the car when outside temperatures are 14° fahrenheit or colder, you would want to drop down to something lighter like a 10w-50. There is a chart in the owner's manual. For coolant, I've been using the Peak Blue European stuff available at AutoZone, there are a number of other options. It's functional and I haven't had any issues. The bright blue color is also useful when there are leaks because there's no confusing that color with any other fluids used on the car, and you can track down the source quickly.

I like to keep the coolant level below the midpoint between the Max and Min levels when the engine is cold, that way when the coolant expands at operating temperature you won’t have overflow loss like you mentioned. Mine is right at about the Min level when cold right now and when it warms up it gets closer to the Max level. I’d recommend adding some fluid to that level and do a couple rounds of bleeding if you think there is air trapped in the system. When the system is fully bled of air, the fluid level should expand to a lesser extent, which will help.

Thanks a lot! I'll try that and see how it goes.

Hey Tony, no problem. Yes, the cap for the expansion tank should be installed before starting the engine in order to build up the needed pressure for venting at the bleeder screw. The caps are typically rated between 15-22psi before they would self-vent air pressure and fluid, so the pressure isn’t that high. The caps can safely be removed when the engine is at operating temperature, as just a small amount of hot air is released when removing the cap. You could use gloves or a rag over the cap if that’s a concern.

@@NC944er Thanks for the quick response. So I can do the venting process a few times in row ? Once i've reached the operating temperature, i turn off the engine, open the venting bolt, close it, start the engine again for a few minutes (how long ?), turn it off etc ? I'm gonna try to do it tomorrow morning.

@@tonylampure8368 Yeah, it’s easiest just to complete the venting cycles back to back since engine temp is already up. Turn off the A/C while running and wait for the cooling fans to kick on, that’s a good sign you’re in the 92°C temp area. Pop the bleeder for a few seconds until the air bubbles stop and you just have solid fluid coming out, lock the bleeder back down, and you immediately start the engine back up. Shouldn’t take more than 5 minutes of running between cycles unless it’s really cold outside.

@@NC944er Good stuff thanks, I'll do it tomorrow and keep you updated. No AC (not very common in the 80s in Europe), cold tomorrow but not too cold (I currently live in France)

@@tonylampure8368 If you had completely drained the block of coolant, or replaced any of the heater lines, it’s also a good idea to set the HVAC to full heat so that coolant moves into and out of the heat exchanger in cabin, which will help get all the trapped air to the top of the block for venting. Best of luck! 👍🏼

Short answer: a lot of time and money.🤣 Long answer: The intake manifold and camshaft housing have been bead blasted and powder coated with satin clear. Most of the steel parts on display have been either replaced or re-plated with yellow zinc. Replacing the fluid reservoirs makes a big difference as well.

Engine Block Drain Bolt M8x16: 900-075-087-03 Aluminum Sealing Ring 8x14: 900-123-105-30

@@NC944er Thanks a lot!

Yeah, the seal for the oil drain plug is 22x27, the engine block drain bolt is 8x14. Here’s some links: www.pelicanparts.com/More_Info/90012310530OEM.htm?pn=900-123-105-30-OEM&bt=Y&fs=0&SVSVSI=1022 www.belmetric.com/aluminum-washers-c-4_2122/ga8x14x10-aluminum-gasket-p-12795.html?zenid=20q8501nlcplhe1oha9t7sag96

@@NC944er You are a life saver.. I just called into Pelican Parts to threw a few of those in my order before it shipped. I just recently had oil get into the coolant system and my guess is that the oil cooler seals went.. I am assuming it will be wise to do a few flushes from the engine block afterwards. Thanks for the really quick reply

@@Seagrams Yep! It’s a bit more work to do the full flush, but worth it to get the system nice and clean.

Hey! I would try to sort out the gauge reading before replacing other major cooling system components. It shouldn’t be bouncing. Possibly a poor connection at the coolant temperature sensor on the engine block? Or a poor connection behind the gauge cluster? A new sensor runs about $50 if you wanted to replace it. Not sure if you have an infrared thermometer to scan the block, but the red section on the gauge should be between 105°-120° C so if the block reads less than that, say 90° C then it’s not really overheating. If your fans aren’t coming on at all, of course that would be a cause for concern as well.

@@NC944er I was just reading about the sensor and thinking that may be the issue. I will give it a shot and hopefully find some good guides on how to do it. Thank you!! I appreciate how helpful and responsive you are.

@@doubled334 Yeah, the sensor is a little buried under the j-boot/intake. It’s the one with the two wires going to it, not the larger plastic connector one. See if you can clean the contacts and terminals and make sure the wires are well seated, could just be loose or dirty causing the gauge to jump.

Hey Howard, yes the process is “generally” the same on the Turbo cars, with just a few extra challenges, like most things on the 951. The bleeder screw is positioned horizontally rather than vertically like on the NA, and it’s partially blocked by the right intercooler pipe, some folks remove that pipe for easier access when venting the system. If you’ve drained the engine block, refilling the block with the upper radiator hose is another challenge as it’s partially blocked by the crossover pipe. You may consider disconnecting the metal return line where it meets the flanged water neck at the top of the cylinder head and refilling there with a funnel and short length of hose attached. Either way, prepare for some mess. 😂

The main thing is to use a phosphate-free coolant made for aluminum engine blocks. I use Peak Blue “European,” as it’s locally available from AutoZone, but there are a number of compatible options available from other manufacturers as well.

@@NC944er Thank you!!

The engine block drain bolt uses an 8x14 aluminum crush washer. Here are some links: www.pelicanparts.com/More_Info/90012310530OEM.htm?pn=900-123-105-30-OEM&bt=Y&fs=0&SVSVSI=1022 www.belmetric.com/aluminum-washers-c-4_2122/ga8x14x10-aluminum-gasket-p-12795.html?zenid=20q8501nlcplhe1oha9t7sag96

@@NC944er Thanks again!

Hey! It’s a 1988 model year.

​@@NC944er should I use the top hose and add directly into the radiator also I've already added to the block through the hose.

@@BennysBenz Hey, no… it’s not necessary to fill the radiator from the top hose connection, just the engine block. The radiator will fill directly from the reservoir/tank when you top up the coolant.

This is taking forever to bleed, it is blowing really hot air in the car now, but the temp gauge is still way up so I've been running the car waiting for the thermostat to open and then shutting off the car undoing the bleep screw then repeat. The expansion tank is going down and I've been adding to it hopefully I'll eventually get this cleared out.

@@BennysBenz Yeah, it can be frustrating. Sometimes it takes 4-6 venting cycles to get all the air out. I generally drive mine and bring a 12mm wrench with me to vent it. Take it to the store or gas station, etc, vent it, drive it home, vent it, repeat. 😂