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'87 E-32 UNIV M-25XP losing coolant/ovr heat

dcsdiego3

Member I
I am loosing coolant and overheating, no visable signs of loss and fresh h2o exhaust not showing to be exhausting coolant.
Any suggestions of what is happening?
Thanks:confused:
 

Emerald

Moderator
Have you checked your oil to see if it has a) risen and b) looks like a mocha shake? Combination of coolant loss, overheating and no visible leaks puts a headgasket leak up on the list. I think you could also be leaking into the cylinders and not really seeing it in the exhaust by the time you go through a water lift muffler.

Do you have access to a diesel compression gauge?
 

treilley

Sustaining Partner
Check the heat exchanger, hot water heater and hoses. Could be a head gasket but check all the easier cheaper stuff first. Could be a case where the HE is holed and you are pushing coolant out the exhaust.

Head gasket failure could show as a milk shake consistency to the oil but sometimes it will only show as white smoke from the exhaust.
 

newpbs

Member III
Water pump

If there is no water appearing in your exhaust you have a problem. I would not look for compression issues or a head gasket yet. I would first find out why water is not passing through the system.

The following would be suspect:

-water pump
-through hull supply valve
-water pump belt
-a blockage in the system (supply hose or heat exchanger)

Without water flowing through the heat exchanger the engine cannot be cooled down.

Paul
 

Emerald

Moderator
If there is no water appearing in your exhaust you have a problem. I would not look for compression issues or a head gasket yet. I would first find out why water is not passing through the system.

Paul

fresh h2o exhaust not showing to be exhausting coolant.


I believe he's pumping water through but isn't seeing signs of coolant e.g. anti-freeze in the water discharge that is visible. At least that's how I read it.

Perhaps we need some clarification on this.
 

Ian S

Member III
Hi David. I had an 85' E32 with an m25 that used to overheat as a matter of fact we warpped the head and subsequently had to replace it, big bucks so watch how hot you let it get. At any rate I now have a 1990 E32 and I have found that both boats are damn near inpossible to bleed out the closed cooling system. I once thought the same as you that I was loosing coolant but it was actually slowly working the air pockets out of the system and therfore accepting small qaunaties of coolant, no leak. for one reason or another the water pump just wont burb that pocket of air out and so the coolant does not flow. Also make sure you have water in your hot water heater tank it makes a big difference on running temps as the coolant exchanges some of its heat with the cooler fresh water in the water heater tank. If you have recently fooled with the system or let it get low to the point where it would ingest air into the system I would say that's your problem. If not I would definately go after the water pump, that is the closed system water pump located above the crankshaft pulley. Capt. Ian S
 

dcsdiego3

Member I
Great Contributions

I am off to marina to check through list of suggestions tomorrow.
Going through the possibilities mentioned, given the rate of consumption I would lean towards a bad exchanger and I am not seeing it in the exhaust. I think I was expecting to feel it and/or see its presence hitting the salt water. I will update as too what I find. Inspires me to get into checking it all.
Thanks for the input! You are all amazingly kind to help.
 

treilley

Sustaining Partner
You would not see it in the exhaust. It would be way too diluted with raw water to be noticed.
 

bayhoss

Member III
Head Gasket

One sure fire way to check for a blown head gasket is to remove the coolant cap (radiator cap to those who think car) and look in with the engine running. Make sure the engine is cold. If the head gasket is blown it will bypass exhaust in the internal coolant path via the waterjackets in the head and block. You will see bubbles that will smell of diesel exhaust.

Best Always,
Frank
E28 Valinor
 

SeaRogue

Member II
Electrolysis ?

There is a relatively rare situation that can cause an engine to overheat that is very difficult to detect. I only know of this happening once, unfortunatley it happened on my previous boat. I replaced the head gasket twice with no improvement. In desperation, I took the engine out of the boat and broke it down completely to find the cause.

In the head there are channels for oil to flow. Small steel plugs are used in those channels to block the flow from those channels into area where they are not intended to flow, like the interface between the oil channel and water areas. Those steel plugs can develope tiny holes that are not visible with the naked eye, and which do not show up under mangaflux testing. I only discovered the problem by applying air pressure to the oil paths in the head at which time I observed bubbles coming from the area of the steel plugs.

If you have noticed that your zinc anodes have been completely eaten away, particularly the one in your head exchanger, that would be consistent with this issue. I noticed that the zincs were gone on that boat when I bought it but did not suspect the extent of the damage caused by that fact.

I hope your problem is not this issue. I mention it only because I had never heard of it before it happened to me and it took a long time and a lot of effort to figure out why I was losing water and overheating.

Good luck.
 

dcsdiego3

Member I
Well thanks to all for the advice. As it turns out I need a new heat exchanger.
So now a new question to you all before I Google off on my own research. Do you recommend a site or company in particular that is a good place to buy a new one?
Thanks
Dennis
 

wheelerwbrian

Member III
One last thing to check, if you're losing coolant and its ending up in the bilge. The freshwater pump has a weephole on its underside --if the bearing fails or the seal, then coolant will run out and down the front of the engine amazingly fast. The solution is to replace it - you could press new seals in but the more dependable repair is a new freshwater pump.

Also, one time I was losing coolant at the water heater. The hose barb was ridiculously short and the hose fell off.

This was on my previous boat that had the same engine.
 

dcsdiego3

Member I
Kiss

Keep it simple I have heard many times.. Turns out it was the hot water heater... Just not enough coolant showing to give it away as the culprit
Thanks to you all!
Dennis
 
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