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jwm · 09-08-2008, 12:01 AM

Did this job recently on my nearly 140,000-mile 1997 ti. In no particular order, some notes/tips:

* I removed the radiator and cooling fan immediately after draining the coolant. I'm pretty skinny and was able to stand in the engine compartment, which was a lot easier than bending over the whole time.

* The valve cover gasket was oozing and I planned to replace it, so I considered removing the valve cover before replacing the hard plastic connecting pipe at the rear of the head in hope of gaining easier access. I decided against it since it didn't seem to get me *that* much extra room, but if you have large hands, it might help. You'd probably want to replace the valve cover as soon as you're done with the water pipe, since there's still a lot of cooling and intake bits to replace at that point and having something fall unnoticed into the cam area would not be awesome.

* It doesn't seem possible to disconnect the M44 squid from the main wiring harness to leave the various sensor connectors in place while removing the lower intake. Most of the harness disconnects with screw-type quick release connectors near the engine compartment fuse box, but part of the harness (IIRC) passes through the firewall with no connectors. I didn't spend a lot of time pursuing this, so I might be missing a way around it.

* I removed the alternator to get easier access to the squid connectors and starter wiring. As a result, the only time I had to get under the car was to drain the coolant. The alternator is a bit of a pain to push out of (and back into) its mounting points, so it might be just as useful to remove the secondary air pump (toward the US driver's side, essentially next to the alternator). The air pump is a lot easier to get out and back in; just two or three easy-to-reach fasteners and it swings out of the way, opening a large space you can use to reach under the lower intake. This could also help during starter replacement, since it might be easier to access the starter's electrical connections from the top. I don't remember if the opening is large enough to remove the starter itself this way.

* Watch the tabs on the coolant temperature sensor (under the intake near the front of the block). I snapped one of mine off removing the electrical connector and decided to replace it, since it's ~US$20 and seems a bit harder to R&R with the intake in place.

* I forgot there's an upper-to-lower intake gasket on both the top and bottom of the PCV shim and only ordered one at first. Oops.

* This is a great time to lube your steering bearing (http://forums.bimmerforums.com/forum...d.php?t=245961) if your steering squeaks since topside access is easy with everything out of the way.

* I also broke one of the water pump flange ears off when trying to press it out. Reusing the water pump fasteners to press it out is tough, since they aren't long enough for the heads to clear the water pump body when you thread one of them in. If you can find them, get some long M6 fasteners to use instead. I finally stood in the engine compartment, grabbed the pump with both hands (a claw hammer or some screwdrivers to pull on the pulley flange was probably involved at some point) and rocked/pulled backwards, trying to put as much of my body weight on the pump as possible while keeping it fairly square to the block. Curse a lot while doing this; it must have helped since the pump eventually popped out.

* Getting the new pump in was straightforward; again, standing in the engine compartment and pushing into the new pump helped. As CirrusSR22 mentioned, so does a light coating of white lithium grease on all the o-rings. The water pump and both plastic connecting pipes popped right in.

* The new pump (bought from the dealer) had a plastic impeller.

* If your car has ASC+T, there's a second throttle body upstream (toward the airbox) of the main throttle body. It operates in reverse; when the actuator pulls on the cable, the throttle plate closes, blocking intake air and decreasing power output. Nifty.

* My injectors were nearly as dirty as those pictured here. I cleaned them up carefully with some q-tips and solvent and have suffered no noticable ill effects. My lower intake also had a decent coating of oil and coke; intake cleaner sprayed copiously did a nice job of cleaning it up.

* I also used the understeer bleeding procedure. I was a little nervous about this since I've heard of people who have bled and bled their cars only to still have air in the system. Some have mentioned that it helps to raise the car to help direct air bubbles toward the radiator, so I tried that first. Fill the raditor up *as much as possible* before starting the engine, since the coolant level drops *fast*. All in all, it was pretty straightforward and I probably bled more than I had to, but once I decided I'd bled enough, the car was fine cockpit heat- and engine temperature-wise. It's helpful to keep the bleeder screw mostly down (don't remove it or loosen it too much, just crack it enough so coolant can escape). This seems to help keep a little pressure on the coolant and lets the maximum amount of air escape while losing the minimum amount of coolant. I bought two gallons of coolant just in case, and only needed one. At the end, I added 3-4 ounces of distilled water only (instead of mixing with coolant) since I didn't want to crack open the second gallon and only needed a small amount to bring the radiator up to the cold level.

* Relieving the fuel pressure wasn't a big deal. I had let the car sit overnight, and I'm not sure how much bleed-back there is. Cracking the fuel line fasteners loose resulted in a smallish dribble of fuel, easily caught with a rag or two stuffed underneath the two hard lines. The Bentley manual says you can also apply compressed air to the Schrader valve on the fuel rail to force any fuel back into the tank.

* LABEL. PHOTOGRAPH. DIAGRAM. Plenty of people preach this and it seems so simple, but I always find myself wanting to skimp on this, and it generally winds up hurting me. Having a sketch of the starter and alternator wiring connections was helpful. If you think you're wasting too much time taking photos or making notes, you're probably doing the right amount.

09-08-2008, 12:01 AM	#34
jwm Junior Member Join Date: Sep 2007 Location: Boston, MA Posts: 14 iTrader: (0) Photo Gallery	Did this job recently on my nearly 140,000-mile 1997 ti. In no particular order, some notes/tips: * I removed the radiator and cooling fan immediately after draining the coolant. I'm pretty skinny and was able to stand in the engine compartment, which was a lot easier than bending over the whole time. * The valve cover gasket was oozing and I planned to replace it, so I considered removing the valve cover before replacing the hard plastic connecting pipe at the rear of the head in hope of gaining easier access. I decided against it since it didn't seem to get me that much extra room, but if you have large hands, it might help. You'd probably want to replace the valve cover as soon as you're done with the water pipe, since there's still a lot of cooling and intake bits to replace at that point and having something fall unnoticed into the cam area would not be awesome. * It doesn't seem possible to disconnect the M44 squid from the main wiring harness to leave the various sensor connectors in place while removing the lower intake. Most of the harness disconnects with screw-type quick release connectors near the engine compartment fuse box, but part of the harness (IIRC) passes through the firewall with no connectors. I didn't spend a lot of time pursuing this, so I might be missing a way around it. * I removed the alternator to get easier access to the squid connectors and starter wiring. As a result, the only time I had to get under the car was to drain the coolant. The alternator is a bit of a pain to push out of (and back into) its mounting points, so it might be just as useful to remove the secondary air pump (toward the US driver's side, essentially next to the alternator). The air pump is a lot easier to get out and back in; just two or three easy-to-reach fasteners and it swings out of the way, opening a large space you can use to reach under the lower intake. This could also help during starter replacement, since it might be easier to access the starter's electrical connections from the top. I don't remember if the opening is large enough to remove the starter itself this way. * Watch the tabs on the coolant temperature sensor (under the intake near the front of the block). I snapped one of mine off removing the electrical connector and decided to replace it, since it's ~US$20 and seems a bit harder to R&R with the intake in place. * I forgot there's an upper-to-lower intake gasket on both the top and bottom of the PCV shim and only ordered one at first. Oops. * This is a great time to lube your steering bearing (http://forums.bimmerforums.com/forum...d.php?t=245961) if your steering squeaks since topside access is easy with everything out of the way. * I also broke one of the water pump flange ears off when trying to press it out. Reusing the water pump fasteners to press it out is tough, since they aren't long enough for the heads to clear the water pump body when you thread one of them in. If you can find them, get some long M6 fasteners to use instead. I finally stood in the engine compartment, grabbed the pump with both hands (a claw hammer or some screwdrivers to pull on the pulley flange was probably involved at some point) and rocked/pulled backwards, trying to put as much of my body weight on the pump as possible while keeping it fairly square to the block. Curse a lot while doing this; it must have helped since the pump eventually popped out. * Getting the new pump in was straightforward; again, standing in the engine compartment and pushing into the new pump helped. As CirrusSR22 mentioned, so does a light coating of white lithium grease on all the o-rings. The water pump and both plastic connecting pipes popped right in. * The new pump (bought from the dealer) had a plastic impeller. * If your car has ASC+T, there's a second throttle body upstream (toward the airbox) of the main throttle body. It operates in reverse; when the actuator pulls on the cable, the throttle plate closes, blocking intake air and decreasing power output. Nifty. * My injectors were nearly as dirty as those pictured here. I cleaned them up carefully with some q-tips and solvent and have suffered no noticable ill effects. My lower intake also had a decent coating of oil and coke; intake cleaner sprayed copiously did a nice job of cleaning it up. * I also used the understeer bleeding procedure. I was a little nervous about this since I've heard of people who have bled and bled their cars only to still have air in the system. Some have mentioned that it helps to raise the car to help direct air bubbles toward the radiator, so I tried that first. Fill the raditor up as much as possible before starting the engine, since the coolant level drops fast. All in all, it was pretty straightforward and I probably bled more than I had to, but once I decided I'd bled enough, the car was fine cockpit heat- and engine temperature-wise. It's helpful to keep the bleeder screw mostly down (don't remove it or loosen it too much, just crack it enough so coolant can escape). This seems to help keep a little pressure on the coolant and lets the maximum amount of air escape while losing the minimum amount of coolant. I bought two gallons of coolant just in case, and only needed one. At the end, I added 3-4 ounces of distilled water only (instead of mixing with coolant) since I didn't want to crack open the second gallon and only needed a small amount to bring the radiator up to the cold level. * Relieving the fuel pressure wasn't a big deal. I had let the car sit overnight, and I'm not sure how much bleed-back there is. Cracking the fuel line fasteners loose resulted in a smallish dribble of fuel, easily caught with a rag or two stuffed underneath the two hard lines. The Bentley manual says you can also apply compressed air to the Schrader valve on the fuel rail to force any fuel back into the tank. * LABEL. PHOTOGRAPH. DIAGRAM. Plenty of people preach this and it seems so simple, but I always find myself wanting to skimp on this, and it generally winds up hurting me. Having a sketch of the starter and alternator wiring connections was helpful. If you think you're wasting too much time taking photos or making notes, you're probably doing the right amount.