Coolant Hoses

[DavidInWilmNC]

After a roadside heater hose repair on my last trip, I'm going to replace all the hoses that aren't really new on my MC-8.  I have a question as to the sizes of the hoses.  They're not listed anywhere in my parts manual.  I'd like to have an idea of the sizes I need before I start removing the old hoses.  I realize I can measure them, but some are not uniform - they're bigger where they fit over the pipes and fittings.  I know I'm going to replace the large hoses near the bumper as well as those that connect the radiators to the brass pipes.  I'm having a hard time determining the size of those, in particular. 

As to coolant, what are most using?  I know there's premixed, 'concentrate' that needs to be mixed with water, and several brands of each that supposedly meet D.D.'s  specification.  I want to use a correct coolant, but, of course, want it at the lowest price possible.  Any other tips or suggestions for this project will be appreciated.  Thanks, as always.

David

[FloridaCliff]

David,

Put in a block heater while your drain down your coolant.

Maybe even thermostats.

Great advice in August, right!   

Cliff

[DavidInWilmNC]

Hi Cliff,

Good advice about the thermostats.  I'll see about ordering a couple, along with the well for the mechanical gauge that's not currently hooked up.  I'm also going to check on that modulating valve for the heater, as the A/C pours heat out when the manual shut-off valves are open.  I'm not sure what the issue is with it, because the green indicator comes on and off, but the heat just stays on!  A 1000 watt block heater is already installed, which is very handy.  Thanks for the input.

David

[TomC]

If you have a 8V-71, standard Prestone anti freeze is fine.  With the dry cylinder liners of the 71 series, coolant type isn't as critical (engines with dry or no liners are, Cummins 5.6/6.7; Caterpillar 3208, 3126/C7; Detroit 8.2, 71 Series; International 6.9/7.3/6.0; GM 6.6/6..  50% mix is ideal, but many use 1/3 coolant also. 
As to the hose sizes, over the years equipment changes can make for different sized hoses than what the bus was built with.  Measuring is the best way.
As to hose type-silicone is the longest lived, but also requires periodic retightening-which can be a problem with the tight spaces in a bus engine compartment.  At Freightliner, we use the Gates Blue Stripe hoses that are a good intermediate hose that generally has a 10 year life, doesn't require retightening.  Good Luck, TomC

[DavidInWilmNC]

Hi Tom,

I've got a 'standard' 8V-71.  I was thinking the same thing, since the 71 series (and the 53 series) both have dry liners, but D.D. is fairly specific about using coolants with these engines, too (http://www.detroitdiesel.com/Public/brochures/7SE298.pdf, page 6).  I'd really like to use standard coolant if possible - I believe that's what's in there now - but I'm wondering if others use standard coolant in their 71's with no problems.  The hoses that are 'newish' are Gates Green Stripe hoses with standard clamps.  They don't seem to have been damaged by clamps, as the silicone hoses can be, and look to be fine. 

David

[Dallas]

David,

I've been using standard green antifreeze in 53's and 71's for as long as I've been working on them.

As far as I know, I've never had a failure because of the type of antifreeze I've used except for once when my service tech put 3 gallons of the red stuff in with the remaining green stuff causing a radiator, waterpump and water jacket full of snot.

In the last 15 years, I've gone to using a coolant filter and nalcool cartridges to keep the ph balance correct. 
I've also gone to using distilled water in the radiator, but I couldn't tell you if it has helped or hurt the system at all.

What ever you do, make sure your system is clean before you refill. Maybe after draining all the old coolant and before replacing the hoses, fill the system with clean water then pour in about a cup of "Bonami" running the engine for a couple of hours to get everything sparkly clean inside.

Dallas

[DavidInWilmNC]

Thanks, Dallas.  It sure looks like standard antifreeze was in the system to begin with.  I'll definitely flush out the system at this point.  Are there any other items I should replace or check?  Would it be worthwhile to do anything to the water pump or other items, or is there no real point?  It looks like it'll be a pain to flush the lines to the front heater cores, but I'll do it as best as I can.  The most work looks to be removing the radiators so I can replace the hoses that connect them to the rest of the system.  Are there any secrets to bleeding these engines?  I know there are lots of points to do so, but I'm just looking for any advice to make this go as smoothly as possible!

I wish I could find out the sizes of the hoses so I could have all my stuff together prior to starting.  I hate to get things apart and then have to go hunt down hoses, etc... especially since I'll be likely doing this over the weekend (incl. Sunday) when no parts stores are open.  Thanks guys!

David

[gus]

Hoses are measured by ID.

Measure each pipe or fitting the hose connects to with simple caliper.

[TomC]

Actually the 53 series has wet cylinder liners.  The series 51 had dry liners, then they enlarged the engine to 53 series and changed to wet cylinder liners, much like when they changed from the 71 series to 92 series.  Good Luck, TomC

[edroelle]

When I changed engine coolant in my 8V71, 2-cycle, I followed the DD recommendation but located this extended life coolant which was much less expensive.

http://www.finalcharge.com/

4 years ago it was about $11.50/gal from the distributor.  The distilled water was about $.75/gal.  As I remember I could only change about 14 gallons.  Total about $85.

Ed Roelle
Flint, MI

[Tony LEE]

"but the heat just stays on!"

I think the valve has to be energised to shut off so it is possible the coil is open circuit or the valve is stuck open. It is located in the front baggage compartment behind the quarter-round cover