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Topic: Block Heater failed on ISM 450 - Question in bold below (Read 566 times) previous topic - next topic

Block Heater failed on ISM 450 - Question in bold below

We plan to move on Monday morning, departing from  I5 coridor Oregon state.  Checking all systems in advance, I turned on the block heater for a test  (with switch at end of bed, red light came on)  and checked amp pull on my Progressive display.  It was pulling around 10 or 11 amps when on.

It was on about 5 minutes when smoke and burnt smell came from engine compartment.  Went inside to turn off block heater as the only likely culprit.  Red light on switch was off, and breaker had popped (as it should with such a issue).

Turned switch off and unplugged cord under the bed.  The cord looks fine where plugged in and as far down as I can see.  Felt where cord goes into box/block, does not feel like burned insulation.  I had expected to see the cord or outlet melted given the burnt smell and smoke.

So the smoke and burnt smell must have been under where the block heater mounts (since cord and outlet look ok).

****  Question: could the burnt element contaminate the coolant, circulate in the coolant, and possibly harm the engine water pump?*****

We had several times in the past where the switch under the bed was turned on by a foot or the vacuum, so it was working in the past. Probably a year plus since I used the block heater.  I had put duct tape over ithe under bed switch  to prevent that from happening again (I know I could have just unplugged it under the bed as well).

We are in no hurry to replace the block heater.  We will use the aquahot to pre heat the engine night before departure (high 30s atnight here right now).

I did a search on block heater, saw the part and part number.  Bigger wrench than I carry. 

**** Just want to verify no damaged element pieces could circulate in the coolant and cause issues.

Part Number Collection 

3309188 - Fleetguard Service Part | Free Shipping 







Dan - Full timing since 2009
2003 U320 40' Tag 2 slide

Re: Block Heater failed on ISM 450 - Question in bold below

Reply #1 –
Shouldn't be a problem as the element inside the tube is what goes. I've changed one one in an 8.3 Cummins and drove a lot of
miles after it burnt out before I changed it.
Peter and Frieda Morin
1999 36ft. U320 Foretravel
Build # 5436
1998 Suzuki Sidekick Sport

Re: Block Heater failed on ISM 450 - Question in bold below

Reply #2 –
You should be able to heat your engine with the AquaHot. At least that is what was explained to me. Turn on the engine and electric or diesel on the AquaHot panel to do so. I have a chassis battery charger/maintainer connected to my block heater switch and don't use the block heater.
Brad & Melanie
2003 U320 3820 1st timer
'97 TJ and/or '85 CJ7

Re: Block Heater failed on ISM 450 - Question in bold below

Reply #3 –
Dan, use the AH.  Electric side probably won't keep up with the demand.  A couple hours with the AH on diesel will be enough unless it is really cold. 

Our coach, delivered in CA in 2001 never had a block heater installed. It was wired for one.
Roger Engdahl and Susan Green
2001 U320 3610 #5879 (Home2) - 2014 Jeep Cherokee or 2018 F150
Hastings, MN

Re: Block Heater failed on ISM 450 - Question in bold below

Reply #4 –
Agree with others that it shouldn't harm the coolant at all.

But something smoked somewhere.  I suggest looking at the outlet that the heater plugs into; I had to change out mine due to age and weather. Polarity problem at home - Page 2

I would also check the resistance across the plug.  For a 1500 watt heater should be around 10 ohms.
You could also check that there isn't any conduction to ground at each power leg of the plug.
John Fitzgerald
1991 U300 (SAI) Side Aisle Island Bed 40'
Detroit 6V92 with Allison Retarder
Meridian (Boise), Idaho

Re: Block Heater failed on ISM 450 - Question in bold below

Reply #5 –

Oh, these covers over the switch will keep it from getting kicked on accidently:
Light Switch Guard Cover Plates Set of 4 - - Amazon.com

As an Amazon Associate Foretravel Owners' Forum earns from qualifying purchases.
John Fitzgerald
1991 U300 (SAI) Side Aisle Island Bed 40'
Detroit 6V92 with Allison Retarder
Meridian (Boise), Idaho