S40 2.0D Throttle Body Cleaning Guide

[SIAMBLUE]

Going to take my TB off today, got a blanking plate as well, looks like I have got the modding bug back again.

[1616six]

Originally Posted by SIAMBLUE

Going to take my TB off today, got a blanking plate as well, looks like I have got the modding bug back again.

Did the exact same today! Didn't make any difference though so I might buy a new throttle body I think.

[Vfifty]

Cleaned my twin TB couple months ago, after having issues with starting in the morning, it definitely helped. After further research on two valves or flaps on TB, one on left (stays open all the time) and other on right (normally in closed position) I found that the one on the right is not closed fully due to flap closing mechanism being faulty.
Searched online for used Volvo twin TB to no avail (they are very rare).
As we know, this 2.0 D engine is collaboration between PSA, Ford, Volvo meaning parts are interchangeable.
To satisfy my curious mind I measured I.D. of the twin TB on V50 2.0D which is same as on Citroen C4( 52 mm) and others.
So I bought TB on Ebay off Citroen C4 in excellent condition for £18, to experiment with.
Below is collection of my findings on TB's for Volvo (twin) and Citroen(twin) and interchangeability options:
-The process of fabrication of TB involves gluing main body (housing) of TB with same diameter part that has valve in it, you can see when look at TB where two parts are joined.
-Fitting positions for both main bodies of TB's are different, so straight swap not gonna work (I knew that from looking at pictures).
-Valves sizes, diameter and length of the valve body are exactly the same in both cases.
-Theoretically, if say, you have faulty(flap) valve it would be possible to unglue( de-bond) valve housing from main TB body and replace it with working one.
-I tried to use standard de bonder to split Volvo TB housing in half, my idea was to do same with Citroen TB and swap valves... De bonder didn't work.
-I think, reason is that manufacturer is not using cyanoacrylate based glue (would be too simple and not strong ) hence above didn't work. So its not just simple chemical reaction involved.
-I am guessing that two parts were joined with thermoset method using polymer, which is less affected by temperature fluctuations. Basically, glue applied to both parts and all subjected to high temperature at which glue sets. To break thermoset bond you need to apply even higher temperature, but you risk damaging parts.
-I kept trying with de bonder for couple more days and gave up.
-Then I thought lets try expansion and contraction method, which involves direct pressure and temperature. Put TB part in the fridge for couple days, then boiled water in kettle, poured hot water straight on joint all around and tried to twist it while holding it above bath. Idea was that hot water makes one part to expand rapidly thus breaking bond with other part, same principle when you heat up nut with blow torch that seized on bolt...didn't work either.
-Without knowing exact description of glue manufacturer is using ( or at least its exact chemical structure) it seems it would be hard to split these TB parts without breaking them.
-Anyway, to be continued...

[SIAMBLUE]

Took mine apart and it was virtually spotless a bit of residue on the sensor so I brushed some brake cleaner on it then sprayed it with circuit board cleaner. Then whilst I was there I fitted a EGR blanking plate.
Next will be taking the front panels off and fitting the ST IC at the same time as the wings and passenger front door.

[ajawoodham]

Just did this job on my 1997 S40 and the pics were really useful; - thanks.

To add to a couple of questions here:

Torx size
I needed T30 torx bit to undo the mounting screws. Also quite tight in there so had to buy a small 1/4" ratchet set to be able to undo them - guessing many people will have something suitable.

Chamfering the circular throttle flap/butterfly.
The starting problem is caused when the flap sticks closed, even against the spring that should hold it open. Cleaning it all out helps, but I found mine wasn't that dirty (I had to call out the RAC once and they cleaned it for me). However it was still sticking. Once it's off and clean, you can push the flap closed with your fingers and hold it up to the light to look for fit between the flap and the body. On mine there was a gap on one side and nothing on the other - helps to explain why it sticks - poor design/tolerance so one side hits the body.

Closing the flap/butterfly a few times I could feel it 'catching' on that side of the body (which is a high density plastic). All I did was got a fine file and took the sharp corner off the edge that hits the body first. Nothing, major, just a few strokes of the file, and it was much easier afterwards - didn't catch at all. Make sure you flush out the filings with the carb cleaner.

Fingers crossed it started cleanly and seems to be OK now. Despite all the gunk in there it seemed to be this 'mechanical' fit that really causes the problem. Hope this helps.

[ajawoodham]

Originally Posted by 1616six

Anyone?

Are you absolutely sure it's rounded off? I did mine today and it took me ages to get to that screw - the rubber seal from the hose on the front gets in the way if you haven't already disconnected that. If it is, only other thing I can think of - slightly risky - is to take out the two screws you can access and see if you can turn the whole throttle body anti-clockwise - see if that loosens the third screw or at least gives you better access. Of course risk is it might shear the screw. Otherwise it is possible to clean partly in situ but not as well - an RAC man did mine once and got it going. What you can't do in situ is file the edge of the flap which is the main thing causing it to stick. If you do it in situ, be careful there is a sensor of some kind which sticks down into the airflow - make sure you don't damage that with your cloth or brush.

[Double_Trouble]

I've not checked (don't have one) but, I assume the parts you're talking about are (plastic) welded together - i.e. they have been heated in the area to be jointed to exactly the right temp then squeezed together till they cool.

This is the way manufacturers generally do this type of work - for them it's cheap, quick and strong. If so then, obviously, you're not going to be able to "debond" the joint with any solvent - without melting the whole thing :-)

If you're feeling brave you could cut it (demel maybe) and the plastic weld them together. If you can't then many body shops do plastic welding - to repair bumpers etc.....

KR
M

[frostbyte]

Video guide:

https://www.youtube.com/watch?v=YFVyhrC40eY

[johnnybguud]

I have a 2005 S40 2.0d

I removed the throttle body the other day - same reason as everyone I guess: spring cleaning - and I noticed that while one of the throttle valves is constantly open and has a spring to remain open, the one of the other side is completely free to move - it doesn't pose any resistance to opening or closing.

Upon further research online someone told me that the second one should be constantly closed and the spring mechanism should keep it closed.

I would just like to get confirmation that this is the case so it would make sense for me to assume that that is the reason why my car has a shaky turn off (both valves are supposed to close upon turning off the engine).



This is also the valve that is constantly leaking (pic below)

[Vfifty]

As per second photo on bottom, the valve which is leaking should be in closed position with spring action resisting when try to push it. It has been mentioned before that oily/fuelly vapours through vacuum hose connected to it cause the constant 'sweat'. If that flap is not closing fully after depressed then spring action mechanism is knackered. Same problem on mine, hence tried to 'experiment' with Citroen c4 throttle body as per my previous post. C4 TBH can be bought for £20 on ebay in perfect condition, whereas for V50 TBH price is three/four times dearer.
Could be causing shaky turn off too. There is anti shudder valve( small orange thing with hoses connected) next to oil filter which suppose to be reducing shudder when turning off engine.