|Topic Review (Newest First)|
|11-13-2011 11:59 PM|
|Capt Len||Further to the heat x for trannie. I believe it should be fresh water cooled in series with the engine hx .Tranny cooler is first in line. Reason? Isolates from salt water corrosion. If raw water pump spits out little rubber bits they don't get caught in small tubes. And if you anchor in an old booming grounds the tiny water borne debris go right thru the big hx and out the exhaust.Been there.|
|11-08-2011 07:57 AM|
|MARC2012||Have had both hx go bad,different boats,when the smaller(trans) went out oil out exhaust.When engine hx added water to day tank.marc|
|11-07-2011 09:44 PM|
|Capt Len||Maybe two different problems. The smaller exchanger is probably for the transmission if it's on salt water does it have zincs or is it vulnerable to electrolysis. I'll bet the brown sludge is normal if it hasn't been flushed and maintained|
|11-07-2011 01:42 PM|
Thanks for all the great suggestions so far. They are extremely helpful. My responses to the issues laid out:
1) Yes, it has been way too long since I changed the coolant and that is likely contributing to the dirty color and needs to be changed regardless.
2) Numerous signs are pointing to the heat exchanger. There is a bit of a sheen on the water from my wet exhaust (even after warm up) and I noticed that after running the engine for a while, there wasnt any pressure on the radiotor cap when I was doing the test this time.
There are two heat exchangers on my engine...one smaller one for the oil and one larger one I assume cools the engine water coolant. I imagine it is a good idea to get both tested. One would think that the leak would be at the oil cooler, but the confusing thing to me is that it is cooled by raw water and shouldnt mix with the engine coolant. Possibly both are bad as the oil cooler sits in front of the raw water coolant....maybe oil comes in to the system from the oil coolant leak then gets into the coolant from another leak in the fresh water/engine coolant cooler downstream?
|11-07-2011 12:13 PM|
|LakeSuperiorGeezer||The closed part of the cooling system should have a pressurized radiator cap. Get the engine warmed up and see if there is any pressure. If there is you know there is no leak in the heat exchanger. However, if there is no pressure it could also just be a bad radiator cap. Caps need replacement about every five years. I’ve seen them go ten. Another thing to try is getting a hydrometer for testing the concentration of antifreeze. Something less than 50% would allow corrosion even if the coolant has been changed every five years to replenish the rust inhibitors. Back a little more than five years ago, antifreeze seemed to last about two years for the inhibitors and scale formation in radiators was also a big issue. Also, if there are chlorides (found in table salt and seawater) corrosion will be accelerated. The most vulnerable parts of the engine for corrosion are the soft plugs on the side of the block and water pump impeller, but with a little luck, you are probably OK, especially if the soft plugs are bronze. I do not know anything about heat exchangers; however, my guess is that since the metals are designed to resist seawater corrosion on one side, the side for the engine is also probably quite corrosion resistant. Don’t forget to check your thermostat. If open just sitting there on the bench, replace it. If you really want to know, check to see if it starts to open at the rated temperature stamped on the thermostat. I did a search and found this http://www.sailnet.com/forums/newpor...mperature.html a posting by HELLOSAILOR, see post number 5 that looks right. I would qualify his answer by saying that a high temperature thermostat in a direct cooled engine in fresh water will result in scale in the engine if the water has a lot of hardness. I saw this on boats in Lake Mead on the Colorado River where scale causing lots of head cracks.|
|11-07-2011 10:41 AM|
I have read that after a long time the anti-freeze coolants lose the rust inhibitor additive
capability? With an iron block engine rust could possibly start forming resulting in the brown color? If the heat exchanger is leaking salt water into the coolant it could perhaps have the same effect. Short of tasting the coolant there may be a way of testing the coolant for salt?
|11-07-2011 08:01 AM|
heat exchanger leaking...known to happen on the older Lehmans...pretty cheap to replace or may get by with a rodding/cleaning/boil at the local radiator shop...
Call Bob or his Son at American Diesel in Kilmarnock, VA....he is the expert on these. He can tell you more in a phone call, than most mechanics can on site.
|11-07-2011 04:37 AM|
Originally Posted by PatrickAlaska View Post
|11-07-2011 12:40 AM|
oil in coolant Ford Lehman
I was changing coolant the other day in my Ford Lehman 4 cyl diesel 85 hp and found some pretty dirty coolant (brownish color, inside of coolant reservior a bit oily too). I immediately thought of a head gasket problem so I bought a Napa combustion gas tester and gave it a try. I followed instructions carefully (got the engine good and warm) and then gave it the test. I used the tester 3 times and received a negative result each time (liquid in tester stayed blue). I suppose this means I dont have a leaking head gasket, but oil appears to be coming in somehow. Any suggestions for what to look for? Some other info....the engine runs like a champ, no loss in power recently, but a bit some blueish smoke out the exhaust. Also, the oil doesnt have a greyish tint and no milky residue on the oil cap (dont see much evidence of water in the heads).
Thanks in advance....Patrick