No (fresh) hot water

[kevin81]

I have E34 1989 with a Universal 25XP diesel. Problem is there is not sufficient flow/pressure from engine fresh water cooling system to heat exchanger in hot water heater. A diesel mechanic has been checking and found:
1. No blockage in hoses from engine to hot water heater. No blockage in hot water heater heat exchanger.
2. The pressure from the thermostat housing appears to be insuffcient to "push" enough engine water through to and through the hot water heater.
3. The return line from the water heater (exchanger in water heater) to fresh water engine pump is not warm.
4. The thermostat and housing are not blocked, i.e. water is flowing through.

Some more info - the boat is in Galveston Bay and in the summer, water temps can be 80's F. The engine has never overheated.

Any ideas? Anyone had a similar problem?

Kevin
S/V Serenidad

 

[rssailor]

no hot water

You might wanna check your heat exchanger to see if it is not blocked. Check to see that the fresh water collant pump is pumping enough fluid thru the engine. Your engine should be under about five PSI of pressure.

 

[Al Emondi]

Water Heater Troubles

Hi Kevin,

If the return line back to your engine is not warm, but the supply line to the heater from the engine is, then I have not clue other to suspect a blockage or busted exchanger in the water heater. If you are not getting any fresh hot water it could be possible that the water level in your water heater is below the heat exchanger. Do you have a check valve on your cold water input to the water heater, is it installed in the correct direction, and is it operating properly. If your heater is draining due to a faulty or non-existant check valve, then that could be why you are not getting any hot water. Does you electrical heating element produce hot water for you?

Al

S/V Mihaska

 

[Sean Engle]

My waterheater was doing the same thing - it was totally rusted out inside. I had to cut it to get it out of the boat - and replaced it with a nice, new stainless Isotemp heater (from Sweden?) - that comes apart (very easy) installation and keeps the water hot for a long, long time (hot showers in the morning - without running the engine up).

//sse

 

[Steve]

Nice HW heater Sean

Sean that was a nice HW set-up, assume it made for an easier contortion when changing or checking the transmission fluid! I'm 6-2 195 and I have a bit of an issue when squeezing in there to get to the transmission! It gets done, but I feel it afterwards !

As for the thread issue, It sounds like one of three things:
1) blocked or constricted HW heater (or in-out lines switched with check-valve)
2) worn water pump
3) air causing pump cavitations

Sounds like the HW is in parallel and not in series plumbing, thus the unit does not cause any effect on the engine cooling. I would disconnect the HW heater and run the garden hose through and see what happens in both directions. At the same time, I would tie the in and out engine lines together and run up the engine and see if line gets hot after the thermostat opens. I think this will tell the tale of either a blocked line in the thermostat housing or a blocked HW heater.

Steve e35-3 #146

 

[Sean Engle]

Sean that was a nice HW set-up, assume it made for an easier contortion when changing or checking the transmission fluid! I'm 6-2 195 and I have a bit of an issue when squeezing in there to get to the transmission! It gets done, but I feel it afterwards !...
Steve e35-3 #146

Steve -

Yeah, I know - I'm 6'1" - 215lbs (seeing your weight makes me want to go back to the gym!) - I figured out the three ways I could get into that compartment - very tight!

I got to my transmission by going up and over the top of the engine - to the back (from the cabin). I also used a pump to pull out the ATF and then a funnel-hose set up with a measured amount of ATF in it to refill.

Never let your ATF get old because of where the transmission is!

//sse

 

[Steve]

Now that's a thought - THANKS

I'll give that technique a shot this spring, not sure about getting an imprint of the injector layout on my stomach... perhaps a blanket laid over would help! I've had these visions of getting stuck in there, I don't think the designers ever changed there own trany fluid! Venture to guess the costs involved in having a yard do it.. Wow they could milk that one for hours... with two guys, one to hold the others feet. :eek:

Thanks… Steve

 

[Steve]

My engine..

You can see my HW is in series with the engine. The positive, -it provides additional cooling capacity; the negative, -additional item to breakdown/leak or clog thus loosing the cooling circuit.

Steve