E36 Cooling System Overhaul Part I, TMS Power Pulley Kit, Rebuilt Alternator, FPR Test

Date: Mid July

Mileage: 148,569

So the M3 had been going through a few little issues recently. First it was the CPS and most recently it was a coolant leak in one of those hoses.

After a spirited drive I noticed the temp gauge has risen a notch past center so I pulled it over to the side of the road. With the engine still running I popped the hood and noticed coolant spraying from underneath the intake manifold. I wasn't able to figure out which hose it was while it was due to the overwhelming mist of hot coolant steaming and spraying everywhere on the intake side of the engine.

I pulled it in the garage to take a look. I tried a little make-shift pressure tester with a bike pump that didn't work out too well. I decided I was just going to replace the old stock hoses. There were 3 that I needed in addition to the upper and lower radiator hose. I knew that to replace any of the hoses deep within I was going to have to remove the intake manifold again. I decided to test the fuel pressure and make sure I didn't need a new FPR while I was in there since the FPR is way in the back and impossible to get to. I picked up the cheaper FPR tester from Harbor Freight that works great as long as you use thread sealing Teflon tape around the threads.

I just used some fittings to run it through the feed line at the front of the intake manifold. Iturned it over and it read right at 3.0 Bar which is exactly the pressure it's supposed to be reading while running. I don't know much more than that about testing the FPR but it looked like it was doing it's job so I could save on not replacing that. 

So like I was saying, with this being a multi purpose track car I figured it would be wise to just order all the coolant hoses brand new. It's a little over $100 for all the hoses for a 95 M3. Upper and Lower Radiator hose, little hose on top, Long hose coming from expansion tank and the spider hose, which I believe was the culprit. There are a few more but I bypassed them as they're for the throttle body and not necessary.

I also decided to put a couple more parts on that I was stock piling like the EMP High Performance Stewart water pump and a set of Turner Power Pulleys. 

Other replacement parts besides the hoses and those just mentioned was a new thermostat, gaskets all around, 2 new temp sensors and of course BMW coolant.  

So I set off by first removing fan clutch the radiator and all the bits up on the front of the car. The fan clutch removal was not too terrible. 

I could have replaced the clutch as well but "part II," which was shortly realized after this maintenance might include an aluminum radiator, shroud and SPAL puller fan. So I left the radiator and clutch alone. It looks like the radiator was replaced 7-8 years ago. At least it wasn't original. 

After that I pulled off the intake bits and the intake manifold to get at the spider hose and the sensors.

I again tried some pressure tests to figure out which hose was bad after finding no visible cracks in any of the hoses. With the pressure tests not giving me anything, I said oh well to my inquisitive side, and continued on with the overhaul removing the old hoses.

I went back to the front. Here you can see the aftermarket aluminum t-stat housing that the PO had installed leaking coolant all over the water pump below it. This was something I wanted to address. 

I pulled out the water pump and t-stat housing. Looks like he didn't use the old style gasket or any RTV causing the leak. There is a paper gasket that goes around the outside that BMW doesn't really sell anymore, that you can still purchase if you want, but I later referenced Pelican which showed the use of RTV gasket maker instead. 

The water pump that was in there appeared to be a metal impeller Graf. Not terrible, a decent replacement  the to stock plastic impeller that originally came on the car back in 1995. I would go with a newer style OEM BMW composite impeller water pump if I weren't using the Stewart pump. I went with the Stewart EMP HP water pump for better temps on the track and less parasitic drag on the accessories. 

Old Graf Pump

The thermostat that was in there was the 96-99 model 92C. I swapped that out for the lower temp 95 M3 88C. 

Old 92C Thermostat

Here you can see all the old residue from coolant and dirt and what not. I cleaned all that up with some scotch brite before installing the new pump and t-stat with housing.

Here's a shot of the difference between the Stewart and Graf pump side by side.

Stewart vs. Graf

I put in the new t-stat and threw a goop of RTV around the housing to insure no leaks, put on new o-ring on the t-stat and snugged it down the housing. 

After that in goes the new water pump.

I then turned my attention to the TMS Power Pulleys. They under dive the water pump, power steering pump and alternator. The dyno shows a gain of 7hp. Well, whatever the dyno says, I know it will feel better. I've always loved the feeling pulleys give the motor by freeing up that power you already have. 

Here's the water pump pulleys side by side.

TMS vs Stock Water Pump

I decided to pull the alternator off for more room and to replace the pulley. I got a little happy with my air tools when I couldn't remove the nut on the back accidentally twisting the terminal right out of the back of the rectifier.

I couldn't really tell how it went back together so I took it to a shop to get rebuilt. No stores sold rebuilt Valeo alternators and a new one was like $350. The alternator pulley is specific to the manufacturer either being Bosch or Valeo. I just bought the TMS pulleys for the Valeo brand I was stuck with that brand unless I paid Turner an extra $65 for the Bosch style pulley because I had already taken the Valeo one out of the box and torqued it down. So annoying.

Anyway I got the alternator rebuilt for $105 with a 4 year warranty. It was a little shop in Culver City. He replaced the brushes and showed me it was charging perfectly. They painted silver which I mean it kind of cheesy when you don't mask things off, but whatever, it's all good now, works well and has a 4 year warranty.

So with that little snafu out of the way I put the rest of the pulleys on the torquing them to about 16ftlbs or whatever it says in the Bentley. I wrapped the old belt around the pulleys to hold the tension while I torque them down.

Onto the coolant hoses. I decided to bypass the hoses coming out of the head to the throttle body connecting a secondary external thermostat. The little external thermostat is supposed to sit inside the air box and tell the coolant to run up to the TB when it is cold outside. Since it's never cold in LA and an iced up throttle body is the least of my worries I decided to get rid of it. It just kind of hangs there anyway with the Eurosport air filter heat shield.

Only problem with this bypass is that it leaves one of the 4 hoses on the spider hose open. Since it's such a unique hose I decided to leave it alone and plug it up with a bolt. So far it's held and not leaked. If there is a better way to do this, I'd love to know!

I got all the hoses routed correctly and put new sensors in the head. I figured the coolant temp sensor is important in the whole scheme of driveability. Maybe not as important as the CTS on the e30 but I decided I would replace it while I was down there. I replaced the other one as well.

Old Sensors

I plugged up the hole where the hose originally came out of with an M12 oil pan bolt. Later I'll use that hole for an actual coolant temp gauge instead of the stock gauge which basically only moves after you've blown your head gasket.

The only thing left to do was clean up the mating surface of the head to the intake manifold, put some new gaskets on and put everything else back together. If you're reading this and want me to go into any more detail on some of the specifics just leave a comment at the bottom and I'll fill you in!



Impressions so far is that the pulleys really make a difference. Engine revs up much smoother and pulls more at the top. The old water pump could have had a rough bearing so I'm not sure if it was a combination of the new pump and pulleys. Temps are in the "ON" range, no leaks and alternator runs smoothly.

UPDATE: I did all this about a month ago. I just got back from the track and now the stock plastic radiator is leaking. Argh...so now it's time to do something about that. Looks like round II is in order.