Simon's take on: 'Mess Under the Intake'

[Victell]

Can the pictures from the original post be updated. Going to try to tackle this soon.

Edit: found some pics here http://www.m42club.com/forum/index.php?topic=2742

[brainspo0n]

Just a little thing I noticed while I was under there

The coolant hose diagram on realOEM.com is incorrect where it shows the two throttle heater plates coming together. They link up by the small ports on the side of each plate. The diagram shows that the bottom port on the larger plate links to the smaller plate.

As if we weren't confused enough! I'm retaining the heater plates because I like the idea.

Classic thread

[MVincken]

I think he said it in this case it was worth second guessing BMW. These hoses are a bad design and prone to failure which lead to poor idling and affect the motors´ performance.
Mind you, in my case I only replaced the vacuum hoses and left the cooling hoses alone since they were fine. Prior to this the car ran like garbage, now it´s back to running like a champ.

I did the exact same thing, and afterwards taped them together with black ducktape, so the possibility that leaking occurs is even smaller.

[spanish pants]

Doing the mess deletion is one of the few times that second guessing BMW engineering actually pays off.

When you do the work it's also a good time to replace your throttle cable clip, maybe airbox mounts, and soft fuel lines, not just in the engine bay, but also at the tank/filter.

I had never thought to replace the airbox mounts. Next on the list.

Honestly i don´t know where al the fuzz is about, i just disconnected the smalle heater plate under the TB. (euro m42, no heating plate between manifold and TB)
so the connected heater plate is just dangling free under the TB

Like you say, secondguessing BMW´s work is often not a good idea, and to be honest i don´t think it´s a good idea now.
This "mess under the intake" surely has a purpose, otherwise BMW just did it the normal way.
heating up the engine ventilation hoses with coolant makes sure the gasses inside the hoses stay warm, and by that they will be easily sucked in by the engine vacuum.
if you don´t warm the gasses the possibility exists that the hoses get clogged, and your engine isn´t ventilated anymore!
this can (in the worst case scenario) result in engine failure.

off course it´s not nice to have your TB & intake manifold covered in engine oil, but that´s a small offer IMO.

I think he said it in this case it was worth second guessing BMW. These hoses are a bad design and prone to failure which lead to poor idling and affect the motors´ performance.
Mind you, in my case I only replaced the vacuum hoses and left the cooling hoses alone since they were fine. Prior to this the car ran like garbage, now it´s back to running like a champ.

[MVincken]

Honestly i don´t know where al the fuzz is about, i just disconnected the smalle heater plate under the TB. (euro m42, no heating plate between manifold and TB)
so the connected heater plate is just dangling free under the TB

Like you say, secondguessing BMW´s work is often not a good idea, and to be honest i don´t think it´s a good idea now.
This "mess under the intake" surely has a purpose, otherwise BMW just did it the normal way.
heating up the engine ventilation hoses with coolant makes sure the gasses inside the hoses stay warm, and by that they will be easily sucked in by the engine vacuum.
if you don´t warm the gasses the possibility exists that the hoses get clogged, and your engine isn´t ventilated anymore!
this can (in the worst case scenario) result in engine failure.

off course it´s not nice to have your TB & intake manifold covered in engine oil, but that´s a small offer IMO.

[roguetoaster]

Doing the mess deletion is one of the few times that second guessing BMW engineering actually pays off.

When you do the work it's also a good time to replace your throttle cable clip, maybe airbox mounts, and soft fuel lines, not just in the engine bay, but also at the tank/filter.

[mjimport]

My parts just arrived today for this project!

[spanish pants]

I finally got around to finishing this. I was waiting for some tubing so i could do the ICV to the intake boot.
When i bought the car i replaced all the hoses with OEM parts. Less than 6 years later and 100,000kms most of them had developed splits.

A definite must do if you have an M42.

[avt007]

Excellent write up Simon! I am converting an M42 to put in my E30 oval track race car. I run an M10 currently, and this post is helping me make sense of all the darned hoses.

A couple questions for you (and any other members that can help), the breather from the valve cover: since emissions are not a concern here, I plan on connecting that to my existing engine breather catch can. There won't be any vacuum applied to the valve cover, but on the other hand, I'm not sucking hot oily air down the intake, either.

Also, since there doesn't seem to be a decent bleed point high on the head, I may use the nipple coming off the side of the head, and run that to my external aftermarket expansion/header tank.

Thoughts?

Thanks

Rob

[SlickAlpinweiss]

Sorry for bringing back this old thread.
I did the mess under the intake..
I haven't yet installed a vac line to run from the valve cover to either the throttle body or intake boot. Would it be okay to just use a PCV breather filter?
I have the icv line into intake boot as well as elbow into tb. I should use a T-connecter to run both pcv and tb into the intake boot? What/where do I get this connector?
Thank you.

[tobias]

Yeah I soughted it out, cheers

[roguetoaster]

Light grey/blue is the forward one on the head. Then there is a black connector aft of that on the head which may be a one pin connector. The oil pressure connector is also black.

That aside, the wire lengths, bends/twists in the wire from age generally show which one should go where. So, with that and knowing one of the plugs/sensors on the head is a one pin connector you should be able to sort it.

[tobias]

So I did this a while ago and I've had a crap idle since and the coolant temp was reading
-69 deg I'm guessing I've gotten the connectors around the wrong way, could anyone tell me what color wires/connectors go to the temp sensor, temp Guage and oil pressure switch? Thanks for the help

[Simon S]

Update:
I had mistakenly purchased an aftermarket “coolant pipe” that started leaking after ~5K miles. Very disappointing. So after going a whole summer putting small amounts of coolant in every other morning, I finally got around to removing intake system to access the pipe last Sunday.

The fuckin pipe was fine. Cleaned up like a new part. No cracks or breaks. When comparing it to a new OE replacement pipe, I could barely tell the difference – but where I did see differences were in the fit and finish of the coupling area that inserts into the block. OE part had a chamfered edge and much nicer general finish in that specific area. The aftermarket pipe had failed due to poor fit at the block apparently.

As far as the “twisted/OE coolant hose” – it was totally fine. Heat cycles on the new hose apparently had effect of taking the “twist” out. I could have reinstalled it, but I cut and twisted a fresh new one on “while I was in there”. Nice to have a sealed system again – and the first hose is now kept in the trunk as an emergency back up.

[brads2002]

Hey Simon,
How is the little factory bent hose you carry a spare for holding up? I routed my original one the same way and it blew out pretty fast right where i bent it the opposite way from the mold. Granted, it had 173K on it so it could have gone just as easily in its original configuration. I am now going to replace everything. Are you still on the first replacement? Looks like its been a few years.
Thanks

Thanks