E46 Cooling System Overhaul

E46 Cooling System Overhaul

Author
Discussion

c3m

Original Poster:

217 posts

128 months

Tuesday 20th January 2015
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Hi guys,

I'm facing a bit of a dilemma about what to do - my E46 330Ci has developed a slow coolant leak. It has become worse over time - at the moment, if I go for a 30-40min drive (25 miles), the coolant level as indicated by the stick would go from max to just above min.

I've done my background reading and know the coolant system on these cars are a weak point - mine is approaching 80k miles. As far as I can see, I have the following options:

1) Try to locate the problem and only replace the affected parts
2) Do a complete overhaul of the cooling system

I'm pretty fond of my car and have no interest in changing it in the near future, so I'm thinking I should just invest and do a complete overhaul. I've got the following parts on my list to get replaced:

- Coolant Expansion Tank
- Radiator
- Water Pump
- Hoses (top + bottom)
- Belts
- Thermostat
- Coolant Cap

[OPTIONAL]
- Main belt
- Alternator Deflector Pulley (idler pulley)
- Main Tensioner Pulley
- A/C Pulley

I'm not an expert but replacing the optional parts seems a bit excessive - what do you guys think?

Also, does anyone know how much such an overhaul would cost? I live in the Sevenoaks, Kent area - can anyone recommend any BMW specialists close by? I was thinking of taking it to ETA Motorsport at Brands Hatch.

Thanks.

helix402

6,877 posts

159 months

Tuesday 20th January 2015
quotequote all
Optional parts depending on the condition of the existing ones.

helix402

6,877 posts

159 months

Tuesday 20th January 2015
quotequote all
Optional parts depending on the condition of the existing ones.

c3m

Original Poster:

217 posts

128 months

Tuesday 20th January 2015
quotequote all
33740 said:
I'd locate the problem first and go from there. It could be a head gasket or a cracked block!
Would there be any way to even locate the leak when it's losing so little coolant?

andyiley

6,980 posts

129 months

Tuesday 20th January 2015
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Of course you can find what is leaking!

It is irrelevant how much you are losing as to whether you can find the source of the leak or not.

It could be something as small as a weak pressure cap.

£15 1 min fix if it is.

broken biscuit

1,633 posts

178 months

Wednesday 21st January 2015
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Why not go for a drive, get the car nice and warm (so the rad is flowing water) then get home and park it on a big sheet of cardboard? Will see any leaks that way. That's how I double-checked for leaks after changing the rad and expansion tank on my e46. Never had an issue once bled.

c3m

Original Poster:

217 posts

128 months

Thursday 22nd January 2015
quotequote all
Thank you all for your advice.

Alex88 said:
c3m, my e46 is going into my local BMW indie today for the same work.

I live in Herts so probably not convenient for you, but I'll happily let you know what the cost was and what was done.
That'd be great, Alex!

broken biscuit said:
Why not go for a drive, get the car nice and warm (so the rad is flowing water) then get home and park it on a big sheet of cardboard?
Unfortunately, the car lives on the street and with the current wet weather, it will be hard to do - thanks for the suggestion, I'll keep it in mind.

STW2010

5,525 posts

139 months

Thursday 22nd January 2015
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c3m said:
Thank you all for your advice.

Alex88 said:
c3m, my e46 is going into my local BMW indie today for the same work.

I live in Herts so probably not convenient for you, but I'll happily let you know what the cost was and what was done.
That'd be great, Alex!

broken biscuit said:
Why not go for a drive, get the car nice and warm (so the rad is flowing water) then get home and park it on a big sheet of cardboard?
Unfortunately, the car lives on the street and with the current wet weather, it will be hard to do - thanks for the suggestion, I'll keep it in mind.
Get home, park it. Run into house and get a sheet of cardboard and slide it underneath.

Get on your hands and knees. A leak the rate of what you describe should be fairly obvious. You will need to remove the under tray to see where it is coming from exactly.

Things to check will be a hairline crack in the expansion tank and a leak from the radiator, as these things bow over time-



I would expect the parts on your (non-optional) list to total around £250, plus coolant. Then about 3 hours labour. I have done the whole lot now, but bit by bit so that labour time is a guess (garages should also be quicker than me). With the radiator out of the way everything else would be straight forward.


c3m

Original Poster:

217 posts

128 months

Monday 26th January 2015
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Alex88 said:
Hi c3m, sorry for the delay in replying.

I haven't got my bill with me, but I'll check it when I get home to make sure I've got this right.
Thanks, Alex - that's super useful!

RyanTank

2,850 posts

131 months

Tuesday 27th January 2015
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Have you had your local spanner monkeys do a pressure test on the system yet?

had a leak on my coolant system late last year and debated doing an overhaul. as they pressure tested it twice and it came back fine! however I left it with them the 2nd time and they managed to trace the leak to a hairline crack in the rad, so that got changed out. I did price up the whole system but my guy told me the rest looked fairly new so no point doing it unless I wanted to for peace of mind.

One thing they did explain was that there may be a need to drain the A/C system to get the rads off.
Something worth bearing in mind for cost of a refill too.

c3m

Original Poster:

217 posts

128 months

Tuesday 27th January 2015
quotequote all
RyanTank said:
Have you had your local spanner monkeys do a pressure test on the system yet?
Not yet, it's booked in next Thursday, will update the thread once I know more.

RyanTank said:
One thing they did explain was that there may be a need to drain the A/C system to get the rads off.
Something worth bearing in mind for cost of a refill too.
Thanks, will keep it in mind.

STW2010

5,525 posts

139 months

Wednesday 28th January 2015
quotequote all
RyanTank said:
One thing they did explain was that there may be a need to drain the A/C system to get the rads off.
Something worth bearing in mind for cost of a refill too.
No, you don't need to touch the A/C system.

Once the fan and expansion tank are out of the way the rad lifts straight out.

c3m

Original Poster:

217 posts

128 months

Tuesday 10th February 2015
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Quick update - the car was put on a lift so that we could take a look underneath. Two components were identified which were leaking: bowing radiator and water pump. Booked in to get it fixed next week, quite happy to properly take care of the cooling system so that I'm not constantly thinking when it's going to leave me stranded on the side of the road.

Barvaux928

49 posts

88 months

Tuesday 10th February 2015
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ye these cooling probs seem to occur on all e46s

if you'll keep the car for a few years i'd consider replacing the entire cooling system, that's what they advise on e46fanatics.com, more info there as well


iSore

4,011 posts

121 months

Thursday 12th February 2015
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Don't bother with the Euro Car Parts EIS rads as they're ste and they always leak from the hose connectors. Go for a Nissens or a Behr. It's worth replacing the thermostat and the expansion tank with genuine BMW parts though. The idlers for the belts can be re-greased, no need to buy new ones.

c3m

Original Poster:

217 posts

128 months

Thursday 12th February 2015
quotequote all
Thanks for the advice, guys. I'm getting the following parts changed (OEM BMW) next week:

- Coolant Expansion Tank
- Radiator
- Water Pump
- Belts
- Thermostat

I've replaced so many things on the car over the past 3 years, hoping not much comes up for a while.

iSore

4,011 posts

121 months

Thursday 12th February 2015
quotequote all
The BMW rad (made by Behr) is £240 plus VAT. A Hella radiator from Euros is about £75 all in and they're good quality. The BMW water pump is a good idea as they do last well - folk moan about them and the plastic impellers but they last a long time. The non genuine expansion bottles can be iffy and they're about £70 from BMW iirc.

I'd swerve the pisstake BMW radiator and save yourself 200 quid but the rest, why not?

Bimmerboss

27 posts

87 months

Thursday 12th February 2015
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Change the whole system, its a seriously weak point.

Water pump, thermo, hoses, top and bottom, rad, and also check your res bottle they go too.

Not a difficult job and all can be done within a few hrs, if your removing the viscous fan ( 32mm ) then you may as well no point chancing it and will give piece of mind in the end.


iSore

4,011 posts

121 months

Friday 13th February 2015
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The viscous is the autos only but yes, if it has one and it looks grotty.........

Bimmerboss

27 posts

87 months

Friday 13th February 2015
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Also replace the water pump pulley, they are made of plastic and does become brittle over time.

But remember do not use any sealant when you replace the water pump and thermo I have seen idiots do this and it never ends nice, from factory BMW do not use any, stick with BMW parts too.

When you bleed the coolant start with the first bleed screw to your right close off once the bubbles stop then move on to the left on the res tank, but remember to turn the ignition to the first position do not start the car to bleed, allow the water to start flowing to the res tank before anything, very easy to do sounds harder Tha is