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Discussion Starter · #1 ·
For the last couple of years the car has caused me intermittent issues. From what I can tell it only loses coolant in large quantities when the engine is running and the car is stationary or stuck in very slow moving traffic. I will see white smoke coming from under the hood. The source of this is really difficult to diagnose, and unfortunately I have little or no money so I must complete a DIY.

About 2 years ago I was worried the car may become a write off. However, I ran it stationary with coolant coming out and with a sealant in the coolant reservoir. This has helped a lot and kept the car on the road.

However, last week I was stuck in motorway traffic intermittently and then about an hour later I was in slow (stop/start) traffic for about an hour and the white smoke came back. The coolant reservoir was empty.

My question is are there any valves (or some other part) that opens when the car is stationary with the engine running? Or something else that happens mechanically when the car is switched on and stationary that could help to explain this? The temperature gauge usually stays around the middle so I don't think it is overheating. Although it is losing coolant.

Thank you for your time.
 

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Lots of potentials but one that is hard to spot and therefore worth examining closely is where the coolant enters the head. Round about cylinder 3, right hand side as you look at the engine standing in front of the car and fairly well hidden under the intake manifold. The coolant pipe from the reservoir goes to a plastic manifold about two inches square which bolts to the head. The rubber seals can go and then the coolant weeps down the side of the block when the motor is running.

Replacement is straightforward if needed - but the intake manifold has to come off for access.
 

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274442


See above coolant pipe right in the middle of the picture - this is actually on my E53 with the intake manifold removed but it's basically the same motor as yours so you can see what I'm referring to.
 

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Discussion Starter · #4 ·
Lots of potentials but one that is hard to spot and therefore worth examining closely is where the coolant enters the head. Round about cylinder 3, right hand side as you look at the engine standing in front of the car and fairly well hidden under the intake manifold. The coolant pipe from the reservoir goes to a plastic manifold about two inches square which bolts to the head. The rubber seals can go and then the coolant weeps down the side of the block when the motor is running.

Replacement is straightforward if needed - but the intake manifold has to come off for access.
Thank you for the reply... I'll aim to check it with a torch and look for white residue around.
The weird thing is the losing coolant when engine on and in stationary / slow traffic.
If I complete long journeys and there are no road works or hold ups the car makes the journey without any issues at all.
If I get held up or it is start and go then it starts losing coolant. :unsure:
 

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Discussion Starter · #5 ·
View attachment 274442

See above coolant pipe right in the middle of the picture - this is actually on my E53 with the intake manifold removed but it's basically the same motor as yours so you can see what I'm referring to.
Thank you so much. Is removing the manifold a 1 man job? Any particular parts required to replace it? I have a decent, intermediate tool set. Lots of hex bits, electric drill etc.
 

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Thank you so much. Is removing the manifold a 1 man job? Any particular parts required to replace it? I have a decent, intermediate tool set. Lots of hex bits, electric drill etc.
I have just pm’d you a copy of the Bentley service manual mate. It’s a must have for all e46 diy’ers 👍
 

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Great work re Bentley. Removal is 1 person and torx / hex / conventional bits. It's just a bit of a faff and you need to methodical. And have 12 bits of rag ready to pop in the head holes to avoid dropping anything in them which would ruin an entire tuesday!

Just to be clear - to examine the coolant entry point above, you don't need the intake manifold off. Just a bright torch will show you any dark patches from weeping. White residue may or may not be obvious - it sort of gets disguised in the colour/texture of the block so you're better off looking for dampness whilst it's hot and running.
 

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Discussion Starter · #8 · (Edited)
I don't know if this can be related? However, a couple of years ago I put an OBD scan on the car and it suggested an issue with the EGR Valve. I did nothing about it. I am thinking to remove and clean the valve. There is a great link here for doing this and it looks like something I am capable of. I was just guessing if maybe somehow the EGR valve not working properly could be causing the coolant leak somehow. Or am I way off mark?
What does anybody think?
 

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Just a thought Andrew but before you take the interior out too to trace this leak.....check the thermostat housing as mine would leak from it & leave pools on the floor yet when pressure tested was deemed perfectly ok! I had to top up every week. Only because the car stayed at the garage overnight did they find a pool of coolant underneath it the next morning. Temperature gauge was always at 12 0clock & never moved while this was going on. These cars always tend to break/ leak /wear from the same parts so check thermostat & water pump before you turn it on its roof.:)
 

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There's always the Amazon coolant dye and UV torch kit I keep mentioning;
although I have no idea what the mention of "RLD2" has to the shape of things :cool:
I think it stands for refrigerant leak detection 😬
 
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