[Don]

Georges,

I am far from an expert on this, but having had an 8V92 and having changed coolant and SCA cartridges as per the schedule I still ended up with a radiator that needed to be recored. I suspect, but have no statistical evidence to prove this, that two stroke engines either need to be run hard and often or they are just prone to radiator plugging.

Unless you have radiator shutters that are not functioning properly or some problem with the fan or water pumps you may have to consider recoring the radiator. The quickest way to convert a perfectly good engine into a boat anchor is to run it hot, so you should not delay curing the problem.

An 8V92 with a good radiator and cooling system is typically going to run about 180 degrees and pulling long steep hills at max power it is unlikely the temps will exceed 195 so the temps you indicate suggest strongly your cooling system needs attention. The radiators can be recored and pulling and replacing the radiator is not a particularly time consuming job.

[Charles]

892’s work best when they “are up on the pipe.” If you are running below 1700rpm’s you are prone to have problems, I keep mine up around 1800 all the time and it loves it. 200* is a death sentence for a Detroit … You had best look into some kind of solution to this problem.

BCO

[Archived]

Georges,

My last coach was a 94 Liberty with the 8V92 and as Jon pointed out, heat is the enemy. Mine had been done by the previous owner and the cooling system was all in good order and it never got beyond 195 in the summer heat. There are lots of possibilities, thermostat’s, water pump, radiator, fan, etc. and if I were in your shoes I would find a good DD place that still has some 2 cycle expertise and get it checked out.

The 8V’s like high rpm’s, especially for cooling, so the temps creeping up in slow and go traffic could well be a sign that trouble is brewing. Let the Forum know where your going to be and maybe someone can suggest a shop with 8V experience or at least a heavy duty radiator shop.

[Georges]

Georges,

I tow a stacker with our 8V-92 power. Last year I thought I was seeing the coolant temp start to creep up. Listening to advice from the community I started to line up a new radiator core and shop to do the work.

Just before heading down to get ‘er done, the shop owner suggested I check to see if the core needed cleaning. Working from inside the engine compartment with a low pressure hose and Simple Green I was able to dislodge a LOT of debris that had taken up residence in the fins. Problem solved!

You might give it a try…remember, low pressure.

Oh yeah, wear goggles.

[Georges]

Thanks for all the quick responses and advice, I figured something is not right and should be handled asap!

The coach is currently in Sanford FL and there is a DD service center right there, so I think I will take it to them for an exploratory.

******UPDATE******

Just found out the Sanford Detroit Diesel service center is no more!

Any recommendations for an honest/ knowledgeable Detroit Diesel repair shop anywhere between Orlando and Fort Myers Fl is welcome. Thank you.

[Peter]

Georges,

Here are the following locations for you:

ORLANDO Florida Detroit Diesel

6850 President’s Drive

Orlando, FL

Telephone# 407-888-1700

Rodney Burk (Field Service Tech) Direct Line# 407-468-0837 He came to Sanford and did a service call with us.

TAMPA Florida Detroit Diesel

8411 Adamo Drive

Tampa, FL

Telephone# 813-621-5651

Hope that this helps you. Ed

[Ron]

OK thanks, I will follow up.

[Georges]

Problem seems to have been solved. Found an excellent,knowledgeable and honest diesel guy in Sanford FL.

It only needed a thorough cleaning, does not exceed 195 now.

PM me if anybody needs his services.

[Georges]

Georges,

Permit me to be the first to burst your bubble. If you have an 8V92 running on the flat terrain in FL and you are seeing 195 temps you have a problem.

It has been quite a while since we had our 8V92 coach but my brain seems to recall on all but the hottest days climbing long steep hills I cycled between 175 to 185 and if I am correct it was usually closer to 180 to 185. Ten degrees doesn’t sound like much and could even be a gauge error, but my gut tells me you need to be in the market for a radiator or new core, sooner rather than later.

How about some 8V92 guys either confirming what I just said or slapping me for giving out bad information?

[Georges]

I meant to say the temp shows below 195, since there is so little space between the 180 and 195 marks and my eyes are not as good as they once were, I would say it probably is running closer to the 185-190 range.

After cleaning it out, the mechanic purposely drove it in very heavy stop and go traffic for an hour in 90 plus temps in Orlando and said it never climbed past 190..

[Archived]

I am siding with Jon on the heat thing. We took a trip to CO and had some heating issues. Rather than take the chance on “Frying” my 8V, I wound up a Core job and have done well ever since. That said, I know what you mean about the Gauge reading, how bout your direct gauge inside engine compartment. My mind was made up without a doubt by using my IR gun on the face of the radiator and finding temp readings all over the spectrum.

[Jerry]

Has the radiator cooling fan been updated to the plastic 9-blade?

[Harry]

My 8V92 is in the shop to diagnose an over-heating problem that I PM’d Jon about a few weeks ago. Shop services a fleet of Prevost buses.

current price on a new radiator is $4,500 and they have had poor experience with the-coring so proceeding step-wise before throwing money at it.

Water-pump fine, plastic fan good.

Replacing thermostats as they have seen stats that look OK but don’t fully open.

Wash external fins. Lots of dirt. They do this often on their fleet.

Flushed the core with a cleaner and got a lot of crap out.

Going to road-test on some hills and see if that solved it.

Interesting observation is that someone removed the thermostatic fans hub so the fan is locked on all the time. On the newest busses Prevost claims a 50-hp boost on the swap to an electric fan.

Just wondering if I would see a decent gain in power or fuel economy if I re-installed the original thermostatic fan clutch?

[Art]

But if you do need a radiator, I had good experience buying a new (not recored) one here: Ace Radiator Independence, Mo. 816-358-2711. $3200 including shipping all copper and brass, no aluminum or plastic. Aceradiatordotcom couple months ago.

[DAVE]

I would like someone to explain to me how electric fans save horsepower.

I know Prevost has switched to them and I am certain that only when cooling is needed do they engage, which is no different than on coaches with an electric clutch.

I also know on low speed clutch equipped coaches move some air, but nowhere near the volume of air that is moved on the high speed. We rarely engage high speed going down the highway so the amount of HP used to drive a fan is likely to be far less than that of the high speed.

But since we cannot get an electric fan to operate without the use of energy it is probable that under low load conditions only modest amounts of electrical energy are required to keep the engine cool, exactly like what we see with the belt driven fans.

But when we climb long steep hills or drive into strong headwinds at high speeds the cooling demand is substantial so at that point a lot of air has to be moved and the power to run electric fans comes from the coach alternators and what they lack in power, possibly from chassis batteries which in the short term will supplement the alternator output.

But if it takes XX HP to drive a belt driven fan it takes a similar amount of power to drive the electric generator to create the power to drive the electric fan. The only difference I can see is with a control module that is precisely regulating engine temps only the exact amount of power to spin the electric fans to maintain a given temp is used and we won’t see the cycling of the fan clutch. When the fan clutch is engaged it is operating the fan at an air flow in excess of that which is needed so we see the temps drop until the cut out temp is reached so that suggests the fan is using more HP than needed and is not as efficient as electrically driven fans that can be controlled to such an extent that only the exact amount of air flow needed is provided.

I think it would be interesting to learn how the electric fans are set up and regulated. I would hope they are more reliable than the fan clutch Prevost installs.