Need a little help with a couple of issues

[Reiner]

First post so hopefully I get this right

Noticed that my sons E30 (his very first car)started to leak coolant so I put coolant dye in thinking he might have a head gasket issue but the coolant only comes out way at the bottom. Can anybody explain to me what might be the issue and what needs to be done to fix it. Also about a month ago it started running really rough and when I pulled the plugs I found that the plug closest to the firewall was all gunked up. Changed all 6 plugs and the car ran great I'm not sure what the cause of the fouled plug could be.
The car is a 89 325is

Please help a dad out that's trying to help out his kid


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[Reiner]

BTW my son bought the car from a post on this website.

https://r.tapatalk.com/shareLink?url=https%3A%2F%2Fwww%2Er3vlimited%2Ecom%2Fboard%2Fshowthread%2Ephp%3Ft%3D425340&share_tid=425340&share_fid=17284&share_type=t

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[Joegreen02]

There is a coolant passage at the rear of the head could be a loose or degraded hose on that fitting.



Fitting shown above could be the culprit


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[Reiner]

I considered that it's just that there is no trace of any coolant higher up. I'll try to check again once it dark out and maybe I'll be able to trace it higher. Before I put in the dye the drops looked just like the light blue BMW coolant. Very clean and not contaminated with any oil or other liquid

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[Reiner]

Ok I ran it again and saw a drop seep down in the seem between the motor and the transmission all along the gasket that's in there. I can't see where it's coming from since I can't see the base of the fitting but I know now for a fact it's coming from much higher up then I first thought. The low location didn't make sense to me anyways. Hoping now it's the fitting and not the head gasket. How do I gain access to the fitting?

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[325e '87]

To me that looks like a drip from the heater inlet/outlet. From under the car you can look up at the two fittings that feed the heater core inside the dash. Right on the firewall next to the brake booster.

[Reiner]

Ok I borrowed a borescope and checked all around the back where the coolant enters the head and it's all bone dry and also no trace of coolant with the UV light. The first trace of coolant that I can find is that it appears in the seam between the transmission and the motor just under the heads and then runs slowly inside the seam down and drips at the very bottom. I also compression checked each cylinder and the below are the results with starting from the front to the back of the car.


140
138
136
141
141
145


the cylinder that fouls the spark plug is 145. Also the test was done with a Harbour Freight test kit. Some of the numbers might be off by a digit or 2 since it's hard to nail down the exact number with the needle and face of the dial


where else behind there could coolant come out that is very clean and not mixed with oil.
also what would you guys guess the issue for the fouled plug could be.

[e30davie]

Your compression numbers seem fine, all within ~10-15%. What they dont tell you use the condition of the valve stem seal. Oily mess of a spark plug with good compression indicate a valve stem seal issue on that cylinder. Thats a head off job really. if it runs ok though dont worry about it for the immediate future.

The quickest way to find a coolant leak is to get one of the coolant system pressure testing devices. Its a little hand pump that attaches to the radiator you pressureise it up and watch the coolant come out.

The only other coolant line in the vicinity of your description is the one that attachs to almost the top of the block, just below the head, you can see if in this photo.



This one or the already mentioned heater outlet is the only coolant lines in the area. Worst case is that its leaking externally from the head gasket, but that is unlikely.

[Reiner]

So I put the light on the highest spot I can trace the coolant to. After it warms up you can slowly see how a drop accumulates inside the seam and then slowly runs down until it comes out way at the bottom. Up high I can't find any coolant that runs on the outside just in the seam. I guess my next step should maybe be to pressurize the system to see if I can find coolant any higher.

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[Reiner]

turns out that a previous owner that had the car built for autocross used an old block from 83 that has a freeze drain plug but in order to access it the shop had to remove the transmission. $30 or so for the part