coolant leakage..

[jimnielsen]

AlfaJack - what about a step by step summary of how to accomplish the removal of the inlet manifold hence providing access to pipe "10"? The manual gives a good guide once the head is off the engine... but I want to disturb as little as possible.

thanks

Jimn~

[wrinx]

You don't haveto remove the inlet manifold, it can be done by just removing the throttle body and dislocating your right arm at the shoulder and elbow....least that's how I did it

wrinx

[AlfaJack]

Removal of head!! Yup I can do a step by step..il start recapping. BTW, are you 100% sure it is this pipe? Well even if its not, its a good one to modify before it does break all together..

Wrinx is right but it is very difficult like that and painful!

1. Remove the straight metal inlet pipe and the 90 degree elbow.

2. Remove the 4 nuts that hold the throttle butterfly. The Throttle cable mechanism will come away now as well with a bit of wiggleing, you might have to manually open the butterfly to the bracket will clear. Put the butterly housing to one side as much as you can - there are 2 water pipes (in and out) which need to be removed as well as a couple of small bore pipes.

3. Diconnect the air temp sensor, and all vacuum hoses and move them out the way as much as possible.

4. Disconnect ERG if you have it.

5. Now the hard bit...look through the gaps closely and see if you can get at the jubilee clips that hold the TB to the trumpets which bolt to the head - there are 8 clipes, 2 on each, if you can undo one for each then it will come off, some of mine had the screw head pointing down and I used some bendy screwdrivers to get at them - was not easy. When I put it back I made sure they all pointed upwards.

6. Remove the two bolts at the front of the TB - they are 10mm and sit at the top of the cam cover.

7. Because the coil packs are attached to the underside of the TB you need to disconnect the spark plug leads so it can come off together.

8. When the clips are all loose and everything disconnected its really just a matter of prising it off the rubber connections and off it comes.


When refitting make sure you connect the map sensor pipe is not snagged on anything - maybe replace it with a high quality piece.

Hope this helps. If I think of anything more I will update.

[jimnielsen]

That's perfect - just what the doctor ordered. No - i'm not certain that that is where the leak came from - but if i pull all this stuff off I will be able to look down the rear side of the engine - the water that came out was very rusty - so I am pretty sure that it will have left a mark that I can see. I am not using the car for a few weeks - so now is a good time to have a look at this issue.

thanks, again.

Jimn~

[jimnielsen]

Its Saturday here - so I am having a go at looking at this coolant leak issue. I have removed the throttle body and I can see that the problem is pipe 10. It seems to be leaking at the small T junction. I can get my arm down there ok (as its small). You can see from the pictures that there is a leak here - you can actually see the water at the base of the small pipe on the "T" that goes back to the filler tank.

The small "jubilee clip" (or hose clamp as we call em' here...) was very loose - so I tightened it using a spanner - so its MUCH tighter now. I can't tell if this is the only problem - or if this has fixed the problem - but it looks like this will have to do for the moment.

I wanted to remove the inlet manifold but the jubilee clips on my Q4 are the factory fitted "clamp" sort that you can't simply unscrew with a screwdriver - and I can see no way that I could ever loosen them without removing the head or the engine.

looking at the situation I could probably remove the pipe 10 without removing the manifold - maybe I should do that - but it may be harder to fit than to remove?

So what do you think? - leave it and give it another run as is? or attempt to remove the pipe 10 and replace it (with a metal one) with the manifold in place??

I had to cut one of the small rubber tubes that goes to the throttle body as the small plastic connector was sorta baked on... where does the other end of this particular hose go to?


jimn ~

[Evodelta]

We have a similar (if not the same) crap rubber T jointed hose on the integrales.
The way I found some high-pressure-only leaks on my track car was to pressurise the system manually with air using the correct tool. You could make your own if you wanted to, you'll soon see the water p*ss out if there are any weaknesses.

The throttle body heater pipes need removing and blanking off at source or (temp job) joining together, it is a good and simple mod for those living outside of the Arctic circle.

If you cannot understand where a pipe comes from or goes to I would suggest following it, otherwise really, there is no hope......

[AlfaJack]

I had to cut one of the small rubber tubes that goes to the throttle body as the small plastic connector was sorta baked on... where does the other end of this particular hose go to?


jimn ~

I think this one goes around the back of the engine bay and in to the fuel vapour system:



As for whether to replace pipe 10 or not. Yours does not look in bad condition but it is a known weak point. On mine, it was weeping so it was replaced but it was a week later that the feed pipe from the header tank burst (90% split). It was obviously weakened by replacing pipe 10. I would say if you have the time to change it blind without removing the inlet like wrinx did then get it done

[jimnielsen]

I tightened the hose clamp on the "T" piece of the rubber pipe, but that has made it leak more - so i will remove the whole pipe "10" today and make up a stainless steel one.

Evodelta - thanks for the tip on removing the water in/out pipes to the throttle body - I will blank them off at the source. I was going to ask on this forum if I could delete these pipes but decided that "discretion was the better part of valor" .

SO that will leave only the large rubber tube that goes to the idle control valve as the only rubber tube on the throttle body - which will make it a lot easier to put undo the lower 2 nuts...




jimn~

[jimnielsen]

Jim, please take note about pipe 10 dimension and post them here.
I?ll appreciate very much if you do.

.. Juan.. here are some pictures of the pipe with dimensions as you requested..

[cuore_sportivo_155]

you might need to make some small changes to the fueling tables if your air temp sensor is located before the throttle body. the car will run slightly leaner if there's less heat transferred from the throttlr body. hardly noticeable though, but since you have the tools to do it, and the time as it seems....

[jimnielsen]

When I removed "pipe10" - the one with the "T" piece behind the engine (and yes its really difficult to get it out...) I found that the small T part could be easily rotated with the fingers in the main body of the tube. - that's why it was leaking -

Question: I am not using a heater in this car, the in/out pipes for the heater are blocked off. I plan to use just a straight piece of hose to replace pipe 10 - and then connect the hose that used to go to the T piece onto the now unused heater connection on the metal pipe that joins to "pipe10". Its the same diameter hole, just a bit further along - and at the same height.

anyone see any issues with this approach? it will just make it easier to fit the tube behind the engine and I wont even need to make up a metal T section???

jimn~

[Evodelta]

you might need to make some small changes to the fueling tables if your air temp sensor is located before the throttle body. the car will run slightly leaner if there's less heat transferred from the throttlr body. hardly noticeable though, but since you have the tools to do it, and the time as it seems....

Won't the air temp sensor pick this up and the ECU make the changes itself?

[cuore_sportivo_155]

only if the air temp sensor is located after the TB, which i don't know in a Q4.... on cars with AFM like the 8v and v6, the temp sensor is located there...

[Evodelta]

It is.

Clever people these Marelli guys.

[AlfaJack]

Question: I am not using a heater in this car, the in/out pipes for the heater are blocked off. I plan to use just a straight piece of hose to replace pipe 10 - and then connect the hose that used to go to the T piece onto the now unused heater connection on the metal pipe that joins to "pipe10". Its the same diameter hole, just a bit further along - and at the same height.

anyone see any issues with this approach? it will just make it easier to fit the tube behind the engine and I wont even need to make up a metal T section???

jimn~

Interesting idea. I think you would be fine with that. Its only a feed for the engine after all, I am no expert though. But I would try it and see how it goes.

[Juan AR155Q4]

Thank you very much Jim!!! That?s exactly the info I was needing.
As for connecting to the heater, I don?t think you?ll have trouble, as they are at the same height.

[cuore_sportivo_155]

It is.

Clever people these Marelli guys.

maybe... the closer you get to the engine, the more heatsoak gets to become an issue...

You'd want the temp sensor as close as possible to the engine, without the sensor soaking up the heat from it, through radiation or conductance... not as easy as it sounds

In my reworked 8v the temp sensor will sit right in front of the TB.... but since i'm going aftermarket with my ecu i can tune it any way i like...

[jimnielsen]

And finally.. when I put all the pipes and everything back together - I decided to leave out bolt "25" as seen in this picture.... seemed to me that the pipe was well enough supported...

As it turns out, bolt 25 goes through to the water jacket in the block.. so it took another hour of taking all the turbo pipes etc off so I could install it!