E36 cooling issues. Part two

[Ahmedsinc 414]

Hey all, noticed the temp gauge on the 325i rapidly climb over 3/4 at the bottom of my driveway this arvo. Had just driven through typical peak hour Auckland motorway traffic with no apparent issues (bout 40 min transit home), and did about 500 ks open road over the weekend without showing any signs of trouble.

Water pump, thermostat, thermo housing, radiator, fan and viscous coupling were all replaced less than 12 months ago so I'd be pretty surprised if there's any issues there. What would be the likelihood of an airlock causing the problem?

as always all constructive suggestions welcome

Edit: have noticed the heater hasn't been pumping the hot air at the same rate as usual, put it down to the heater tap being full of gunge - another job I've been procrastinating over.

Edited August 27, 2012 by Ahmedsinc

[Michael. 2313]

Quite possibly an air pocket has formed in the cooling system... perhaps check the level is correct and that the system has been bled of air.

[Ahmedsinc 414]

Quite possibly an air pocket has formed in the cooling system... perhaps check the level is correct and that the system has been bled of air.

Level was about a half inch below cold mark whilst engine still hot. topped back up full, opened bleeder screw yada yada. Just ran motor back up to operating temp, needle now sitting rock steady at usual half point. oddly, heater still doesn't blow hot air unless revs at 2k or higher. Am now thinking a possible blockage in heater hoses? Can't get arm in to have a feel (spatial co-ordination isn't my strong point and I'm really sick of burnt hands) but given the amount of sh*t that came out of the motor and hoses when I replaced the radiator it kinda seems like it might be part of the problem? Further to the point, I haven't noticed any green drips under the car, so how the hell could I have needed to put in nearly 2.2 litres of water. Oil is clear of water and vice versa.

Edit: Check coolant level is still showing on the check unit. Given the overflow bottle is totally opaque how does one know if it's overfilled?

Edited August 27, 2012 by Ahmedsinc

[Steve K-B 51]

check the coolant when its cold, start it up and open the bleed screw.

It sounds like you have a leak somewhere that has created an air pocket. Could have a blowen head gadket/cracked head but I would be suprised if it was that that was the case after not having any over heating problems previously.

First thing I would do is get it pressure tested at a workshop.

E: I would also open the bleed screw once again when its hot just to check but close it when you see a constant flow of coolant. Dont burn your self

Edited August 27, 2012 by Steve K-B

[hotwire 352]

Firstly, coolant can go straight into combustion & out the exhaust - & not into water or oil. (head gasket/head)

You say coolant was just below cold level - but you put over 2 litres of water in? Must have had a hell of a lot of air in the system. This too would make me suspicious. Leakdown test/snifer test/pressure test in cooling system.

Coolant warning still on - a fault in the circuit or level down again (more likely)

Secondly, heater not hot. Very common for heater taps to fail. Check in & out hose temperatures

Dual climate air system? These have two taps - L/H side of firewall

Edit: Got beaten to to the reply by Steve K-B

Edited August 27, 2012 by hotwire

[Ahmedsinc 414]

Firstly, coolant can go straight into combustion & out the exhaust - & not into water or oil. (head gasket/head)

You say coolant was just below cold level - but you put over 2 litres of water in? Must have had a hell of a lot of air in the system. This too would make me suspicious. Leakdown test/snifer test/pressure test in cooling system.

Coolant warning still on - a fault in the circuit or level down again (more likely)

Secondly, heater not hot. Very common for heater taps to fail. Check in & out hose temperatures

Dual climate air system? These have two taps - L/H side of firewall

Edit: Got beaten to to the reply by Steve K-B

Yeah, the volume of water it took makes me highly uneasy. Check light came on when overflow tank was still full, am guessing the circuit/sensor has seen better days. Rechecked oil cap & dipstick, both are squeaky clean, oil service was done less than 1000ks ago. Have noticed normal amounts of condensation from exhaust on cool mornings but it certainly didn't seem out of the ordinary, i.e no visible exhaust when at normal temp.

Coolant has remained at full level since last topup, is a roadtest still sensible or am I running the risk of blowing the HG completely to bits? And can anyone recommend a service agent close as possible to Ellerslie? Would rather take it to Glenn but am a bit nervous driving it that far in current state.

[hotwire 352]

You won't necessarily notice water out of exhaust. It is natural when cold to see it, not when hot as it evaporates.

I would say you will be safe enough to drive it to Glenn, go for a shorter run first & monitor the water - if it doesn't drop - you should be right. Damage, if any is already done, as long as you don't run it out of water you will be ok.

Just be aware that the temp gauge will only read water temperature - not air. Meaning if the the coolant drops below the temp gauge sender - the gauge won't show hot.

Coolant warning - did this just fault after you topped up the water? Did it come on initially to indicate low before you topped it up? Make sure the sensor is not sticking in the reservior

[Ahmedsinc 414]

Check warning has been popping up intermittently, had put it down to a crappy sensor (has shown up on diagnostic scan before). Was still showing after topping up water so will have a look at whether it's just sticking. Whats the best way to sort it? Piece of wire down the spout and give it a gentle nudge?

As for the heater, thankfully its the old A/C so just the single tap. Have got another lying around somewhere, will find out if I should bother changing it out first.

Will be bussing tomorrow (shudder) so will take it for a gentle road test once I get home. Typical, these things have to happen at less than ideal times

[Ahmedsinc 414]

So finally got around to replacing the coolant reservoir level sender, the floater had been fused into low position with an amazing amount of shyte. Swapped out the reservoir for a newer unit that is a little easier to read. Drained out dodgy old nulon coolant and replaced with BMW branded blue stuff, removed all coolant & heater hoses and heater tap, cleaned gunge out of all parts and duly replaced.

Took the car in for its WoF this morning, the inspector pointed out an oil leak which I've been hunting for ages (yet another pita job) and three or four blue drips on the exhaust side of the block right by the firewall. I did notice evidence of coolant dribbling at the heater tap, will need to reseat & tighten the clamps there. Is there any chance the drops on the drivers side of the block could have migrated from the heater taps or have I seen the first concrete evidence that the HG has gone?

On the plus side, finally spotted where the block coolant plug is!

Will be seeking a coolant compression & cylinder leak test ASAP, does anyone know of a workshop within safe distance of Ellerslie that can do the test on a Sat morning? My preference is to take it to Glenn but weekdays are a bit difficult at the moment. Any idea what a new gasket is worth, assuming the head hasn't cracked?

*Edit: Still no recent history of overheating

Edited January 19, 2013 by Ahmedsinc

[Ahmedsinc 414]

Anyone?? Or is everyone but me at Hampton Downs or the hotrod show at Kumeu today?

[Ahmedsinc 414]

So on further googling it appears there is a flange on the rear of the head that sometimes lets go. Anyone else had similar experience with this? There is evidence of coolant dripping on to the exhaust manifold between cylinders 5 & 6. Also only seems to be dribbling when hot, would have thought a HG leak would be present all the time? Or am I on the wrong track here?

Part 3 & 4 in diagram

[Ahmedsinc 414]

Bump.... anyone else here had a similar issue in the past?

[*Glenn* 854]

The alloy water outlet (No3) is common for corroding. A pressure test, mirror and torch should be enough to determine your problem

[e30ftw 410]

Probably is the rear outlet, But now that I remember, back when I did an m50b25 swap into my e30 I had a similar issue of water leaking veeery slowly but it was coming out. The engine was from a e36 325i, M50B25 (non vanos if it matters).

I got it inspected at Jeff Grey locally in hastings and it was determined that it was a problem from manufacture and there was a re-call for it back in the day? Seemed weird, Kerry who sold me the m50 hadn't heard of it either, but ended up having to do the headgasket on it as it was seeping from the back under #6.

I had hoped it was that back outlet too, But sadly not lol. Worth getting it checked out though.. Pic's if interested. First pic is looking upwards at exhaust manifold / side of block, you can see a little trickle of coolant.

[Ahmedsinc 414]

Really wish I'd had the time to take some photos whilst in the VTNZ pit From memory the drips were slightly forward of the rear edge of the block, my initial impression was too far back to be from the HG, but then water has an annoying habit of migrating in odd directions.

Cheers for the tip Glenn, prior to Saturday afternoon I had no idea there was a hose all the way back there....... damn inconvenient spot it is too!!

I'm guessing to remove the intake manifold would require new seals on refitting, any idea what the set will cost? Kinda hesitant to meddle with the fuel rail, I presume all kinds of havoc would result from an air lock or vacuum leak from a badly seated o-ring :s Any tips on how best to deal with this issue?

S'pose I could get around the issue by shoving an M60 or LS1 in the hole instead, would have a really pissy mrs to deal with though