Porsche 944 Overheating?

[GTR34]

In the mean time, I thought I'd post up a pic of my trunk mod. I noticed the trunk quit opening after I pressed the trunk button (trunk lock is frozen) so, after ordering new trunk pins (because the right side was broken off) I added two springs from fastenal and a washer below each spring to prevent the spring from going down into the lock hole. The trunk now pops open every time!

[GreenWater]

I thought of something like this when I was making the hatch pin seats but couldn't figure out a way to actually make it work and I am wondering how yours works. I would think the washer at the bottom of the spring would need to be much bigger. To either catch on the locking arms or catch on the lock body itself. I am very curious as to how they are working.

[HondaDustR]

Originally Posted by GTR34

In the mean time, I thought I'd post up a pic of my trunk mod. I noticed the trunk quit opening after I pressed the trunk button (trunk lock is frozen) so, after ordering new trunk pins (because the right side was broken off) I added two springs from fastenal and a washer below each spring to prevent the spring from going down into the lock hole. The trunk now pops open every time!

Must...have...details!

[Gawernator]

It really is a bit difficult to shift into 1st while moving at speed... hard on the synchros if you don't rev match really well.

[GTR34]

Looks like I'm learning how to rev match/ double clutch! Truth is, I'm not quite sure how it works either. I'm not sure if the washer goes down in or actually stops. My theory is that despite what I intended, the washer actually goes into the hole and makes a tighter seal (there's no play in the trunk when it's closed) but the spring will not fit in the hole, so it stays behind. Then when I press the button, the spring pressure pops the trunk up. I'm not sure what springs these are, I can get more details on them though ( my dad picked them up while I worked on other stuff) but you can buy them at fastenal

[GTR34]

I was also wondering what it sounds like when fans are on full "oh crap the engine is going to melt" speed, because I'm not sure I've heard them kick in at full force. This might lead me to believe that the thermostat is either bad or installed wrong, because the thermostat begins to rise almost immediately after the car turns on after sitting for a while.

[HondaDustR]

Originally Posted by GTR34

Hmm, I see. Well the shifting method seems to make sense, but is double clutching required or could I just rev match?

They are two complimentary entities. Since I'm never sure just what people know and don't know, I'll explain. Rev matching is basically what it sounds like and is done after you actually get into the new gear you are shifting to. Once you have already shifted to the new gear, you either wait for the engine to slow down to the correct rpm it would need to be for the next gear before letting the clutch out in an upshift, or blipping the throttle to raise the revs to near the required amount for the next gear before letting the clutch out in a downshift. You are taking that extra second to make your clutch last a lot longer by working the throttle to put the engine where it needs to be for the new gear rather than just making the clutch force the engine to the speed it needs to be in. It becomes more important for clutch life the higher the rpm range you are working at, as let's say hypothetically you are in 3rd at 1500 rpm and you want to downshift to 2nd. The engine will only have to speed up to maybe 2200 rpm to match the shift. Not too terrible to ask the clutch to do that. If you are in 3rd at 3000 and want to downshift into 2nd, the engine will have to be something like 5000 rpm...a lot more work for the clutch! Just use the throttle to kick the engine up to around 5000 rpm while the clutch is in and you are shifting into 2nd, so that when you release the clutch, the engine is already at the rpm it needs to be. You will actually have to overshoot the rpm mark a little to allow for any latencies involved in your execution, plus I find it easier to overshoot the mark and just catch the matched rev as the engine slows down rather than try to shoot up to the mark exactly or even catch the mark on the way up the rpm. Your clutch will thank you.


Double clutching is how you actually get into the new gear without beating on the synchros (or if the synchros are shot, or the gearbox is non-synchronized). It is only required for downshifting. So say you are rolling along in 4th gear at 2000 rpm and someone is sucking at life driving 10 under the limit in front of you and you need to pass. In order to be in 2nd at the current road speed, let's say the engine needs to be at 4500 rpm. So think about what needs to happen in order to not work the synchros... the transmission input shaft has to be somehow sped up to around 4500 rpm before 2nd can engage. Without this technique, the synchros are the ones doing that work and it is a lot of work on these cars as mentioned before. What you do is let off the gas and put the clutch in just like for a regular shift, drop the stick into neutral, kick the engine revs up to around the target rpm while releasing the clutch again to speed up the driveshaft/input shaft, push the clutch right back in and push the stick into 2nd (or whatever gear you're shifting to), and then rev match to engage the clutch in the new gear. The part you do in neutral happens very fast once you get the hang of it. You are basically kicking the revs up while letting the clutch out and then right back in, making the timing such that the clutch is engaged at the same split second the revs are near the target, and then shifting immediately after the you push the clutch in so as to not allow the driveshaft to slow down again. When everything is timed correctly, the stick will go into the lower gear with minimum effort. Once you learn the gear spacings and practice the technique, it is nearly as fast as a regular downshift. It's much easier to show than to explain.

Now you can also help the synchros in upshifting by just applying light pressure to the stick once you push the clutch in and let the revs drop, and once the input shaft speed matches, the stick will just drop into gear. That's the same shifting feeling you want in a properly executed double clutch downshift.

[GTR34]

Alright, that's what I figured it was. At the moment when shifting into first, I just wait until the car is nearly stopped to engage first. Seems to work pretty nicely, I'll have to get better with my clutch control.

So, I drove the car 80 miles today without any incident. Though the air was cooler (about 50 degrees), the temperature gauge once again hovered around the top white mark, never exceeding it this time. After I pulled in the driveway, I immediately popped the hood. I felt the intake manifold and it wasn't scalding, you could hold your hand on it for a while actually. I'm starting to seriously believe in false thermostat, but bear in mind I'm still willing to replace everything rubber in that engine to be on the safe side.

[GreenWater]

I think with the temp gauge where it is, that you wouldn't be able to touch the intake manifold. I thought it would be hotter than that. Maybe I am wrong. It almost sounds like you might have a gauge problem, in some form. If you can, take a temp reading by the coolant temp switch in the engine block.

[GTR34]

Alright, but I'm not sure I can because I don't have an infrared heat gun. Any other methods to check?

[Gawernator]

The intake manifold really doesn't get that hot relatively. Try touching the cam tower, the coolant bleed plug, radiator hose etc

[GTR34]

I'll make sure to try that next time. I'm getting quite a bit of accessory belt noise from the air conditioner pump and sometimes when I turn the front window defroster on. Any ideas on how to quiet it? It's incredibly loud.

[Gawernator]

Like.. A loose belt slipping or the pulley is bad? Describe noise please

[GTR34]

I believe it's a loose belt because it's a really loud squealing noise. They're relatively new belts so maybe they're not tight enough?

[HondaDustR]

Ive found the alternator belt needs to be fairly tight to not squeal. Additional electrical load will increase the tendency to squeal. Try tightening it and see if the squeal goes away. If it doesn't, pull the cam belt covers immediately! It could also be the power steering if so equiped, but that should be easy to single out, as it should be easy to induce squealing when steering in a parking lot, etc.

New belts always stretch a lot, so if the alternator belt is fairly new and hasn't been retensioned since initial installation, I bet you it's that. It doesn't have a spring tensioner like newer cars.

[GTR34]

After a good amount of driving, I grabbed the radiator hose to find out that it was pretty warm. I could hold my hand on it for a few seconds but it was pretty warm. The intake manifold was also very warm and the valve cover was just plain hot. (Isn't that rather expected, though?) I would like to get a real temp reading on various parts of the block. Also, are these engines supposed to crackle and pop after a good day's driving or is that not a characteristic of aluminum blocks? Mine doesn't do that even after a long drive.

[Gawernator]

When cooling off you definitely get that sound.. And harbor freight has a cheap temperature gun

[GTR34]

So, your car does it? Why doesn't mine? I swear I turn off the engine and it's completely silent under there. Is that bad?

[HondaDustR]

You must not be driving it hard enough.

You should check your temp sender and gauge in case it's off.
Sensors and Gauges - Information, Troubleshooting, and Testing

[GTR34]

So, is it good that my car doesn't crackle meaning its not that hot or is it just so hot that the metal doesn't contract after a while?