What a (tr)ucking day

So I had the task of moving a pantech-trailer with some fully loaded furniture several hundred kilometers.
So I just started my trip, done maybe 15 to 20km.
Then a notice the oil pressure meter doing a funny dance, damn this unreliable stuff, I thought. I banged it a couple of times with the fist, nothing happened, except the slight pain in the knuckles.
Suddenly, like Juliet's final dance before her painful demise, then needle tumbles to Romeos side (then line indicating 0 bar).
What now?
Some more banging of the instruments took place, then I noticed the steady climb of the temp gauge from its normal 80 position towards 100.
I switch on the indicator, moved the truck onto the shoulder of the road and switched it off. The top gear crew would have been impressed, it took only a few seconds, (some brilliant emergency driving there on my part).
I jumped out and was greeted with a massive river of oil underneath the huge 15000cc V8, not good.
So where do you think the oil came from.
Interestingly enough, a blown water pipe that connects to the radiator.

My first thought is you don't go 'banging' such vitally important dials

If your oil pressure gauge starts going 'funny', stop immediately and find out why - you may have caused more damage by not stopping sooner?.

As for oil coming out of the burst water hose? - sounds fairly simple - a blown head gasket, forcing your oil into the cooling system, which in turn over pressured the hose and burst it.

Doesn't sound terribly cheap though?.

Yeah I know. These meters are a bit old and sometimes do a bit of a dance. Normally a well timed tick sorts them out.
I think the engine is largely intact, it starts easily, has no funny sounds, etc.
We had to start it again to get the trailer off its back.
I also leaned towards a head gasket, or worst case cracked head.
But there could be something else, these truck are fitted with a heat exchanger, to cool the oil. Interesting device, a pipe carrying oil enters the device and spirals like a coil through the system using radiator water to cool the oil. That could also explain the oil in the water pipe as well as the pressure that burst the pipe, as the oil gets pumped.
Or maybe I would just want it to be that.
But I'm still leaning towards the head problem.

Luckily this type of engine also has individual tops and heads, etc. for each cylinder, you just fix the one/s affected. Cool.
But redoing the whole katooti will cost about R65000, damn, I can buy half a car for that.

Does the truck have an oil cooler?

On some vehicles, hot engine oil is diverted through an oil cooling unit that is simply a heat-exchanger...oil on one side and coolant on the other. The cooling system is typically under far less pressure (approx. 1 Bar) than the lubrication circuit (approx. 3 Bar-ish), therefore any failure within the oil cooler will result in oil being pumped into the cooling system.

Oil pressure will drop (obviously) and since the oil has a requirement to be cooled, it can be quite certain that an exchange will raise the temperature within the cooling system. The excess pressure from the oil circuit, combined with the subsequent further heating, cannot be vented sufficiently via the cooling system pressure cap, so something else usually gives...such as a hose.

EDIT: Crossed posts. The head gasket is less likely from the symptoms described.

Yip Mickster, that's what I was talking about.
Hope it's that.

I'll start stripping tomorrow, should reach the heat-exchanger at some point.

The same sort of thing can happen in a car with an automatic. A few loops inside the radiator cool the automatifc transmission fluid. The lines runs out and the transmission is ruined.

I disconnect the transmission from the radiator and install a separate cooler that runs in air. It is said that they do a better job of cooling anyway.

The truck is still stranded in an industrial area, hopefully will tow it still today.
I really would like to find that heat exchanger to see what it's doing.
But believe I'll have to make a visit at Merc commercial first to see where the thing is located.
Maybe it's a good idea to run it separately like you said 3v0.
If it's the cause of the problem, I'll see if I can convert it to an independent republic.

Hey arrie,

did ya find out what failed on the truck yet?

We believe it's the oil cooler.
We have not yet started working on it, as we are in the unfortunate situation of keeping the boat afloat at this point.
A lot of time now goes into keeping the other truck and crew a well-oiled machine, as it's the last of three.
Last year our oldest truck, the one my dad started with seized up.
It had more than 3 million km on the clock, but the engine have been overhauled two years ago.
Overhauling it again would cost more than it's worth.
We believe we'll have the oil cooler problem sorted next month (hopefully early), and back on the road.

Thanks for your concern. I'll update this thread as new info becomes available.

arrie said:

We believe it's the oil cooler.
We have not yet started working on it, as we are in the unfortunate situation of keeping the boat afloat at this point.
A lot of time now goes into keeping the other truck and crew a well-oiled machine, as it's the last of three.
Last year our oldest truck, the one my dad started with seized up.
It had more than 3 million km on the clock, but the engine have been overhauled two years ago.
Overhauling it again would cost more than it's worth.
We believe we'll have the oil cooler problem sorted next month (hopefully early), and back on the road.

Thanks for your concern. I'll update this thread as new info becomes available.

Click to expand...

Best wishes.


kv

3v0 said:

The same sort of thing can happen in a car with an automatic. A few loops inside the radiator cool the automatifc transmission fluid. The lines runs out and the transmission is ruined.

I disconnect the transmission from the radiator and install a separate cooler that runs in air. It is said that they do a better job of cooling anyway.

Click to expand...

A transmission pan with moving air past it typically does a better job at cooling than running fluid through an already hot radiator from the motor. My truck employs a deep sump pan, exposing it to better underchassis air flow, and an auxilliary cooler that is mounted infront of the radiator and about half its size to boot! I'd like to swap out the OEM pan for a ribbed, cast aluminum pan but they cost $$$$.

I was driving a company car on the highway when the oil pressure warning light indicated low pressure so I pulled over. I had the oil and filter changed earlier in the day and the oil filter fell off on this trip. I guess the kid who did the oil and filter change forgot to tighten the filter.

The car's camshaft failed a couple of weeks later.

Air cooled more surface area and extra oil held in it.

HiTech said:

A transmission pan with moving air past it typically does a better job at cooling than running fluid through an already hot radiator from the motor. My truck employs a deep sump pan, exposing it to better underchassis air flow, and an auxilliary cooler that is mounted infront of the radiator and about half its size to boot! I'd like to swap out the OEM pan for a ribbed, cast aluminum pan but they cost $$$$.

Click to expand...

Hotpoint refrigerators had a Compressor that used a u shape tube an over sized loop came out all the way to the front of the unit then back to the Hermetically sealed can over the Compressor. It had the extra oil in it as well without overfilling the can. The ambient cooling kept the compressor much cooler than others of it's size. Their was also a little a small amount of air flow created by the Condenser Fan.

I think it's better too!

kv

audioguru said:

I was driving a company car on the highway when the oil pressure warning light indicated low pressure so I pulled over. I had the oil and filter changed earlier in the day and the oil filter fell off on this trip. I guess the kid who did the oil and filter change forgot to tighten the filter.
The car's camshaft failed a couple of weeks later.

Click to expand...

At least it was not your car... You know what the next best thing to a offroad highway vehicle is?

A company car

HiTech said:

A transmission pan with moving air past it typically does a better job at cooling than running fluid through an already hot radiator from the motor. My truck employs a deep sump pan, exposing it to better underchassis air flow, and an auxilliary cooler that is mounted infront of the radiator and about half its size to boot! I'd like to swap out the OEM pan for a ribbed, cast aluminum pan but they cost $$$$.

Click to expand...

Seems these types of oil coolers have caught a lot of flack as to failing this way. I have not yet looked at the MB diagrams to see exactly how they channel the water to the cooler, but have an idea what's going on inside the cooler itself.
The thing is, you have about 30 litres of oil inside the engine, and although the sump really does come low down, I suppose the german engineers at the time felt that the oil is running a bit too hot, and too hot oil has its properties altered, so cannot protect the critical bits enough.
I would also choose to have a separate cooling system for the oil if I had it my way. Will see what I come up with when I start the work on the truck.

Be it transmission or engine oil, the pans that are most effective are these types:

**broken link removed** **broken link removed**

HiTech, I would agree, some type of fin is required.
Unfortunately the MB sumps are rather smooth, but will catch a lot of air though.
I would also not really go after market sumps, too expensive.

I used to have a small air-cooled two stroke motorcycle way back, it looked more menacing than today's cpu coolers, but did one heck of a job.

I'm washing all the oil off tomorrow morning, and then I'll start to strip, starting with the oil cooler/heat exchanger.
Wish me luck.

arrie,

regardless of the findings, be aware that you will have to flush both the oil and cooling circuits after repair. I'm still inclined to suspect the oil cooler, so suggest a simple test:

If you have access to a cooling system pressure tester, reconnect the blown-off rad hose and refill the cooling system. Clamp off the two coolant hoses on the oil cooler and pressurise the cooling system. If the system holds pressure, release one of the clamps and watch for any pressure drop. This will confirm the suspected oil cooler. Otherwise, if the system loses pressure with the hoses clamped, with no external leaks, you may be looking at a head gasket/cracked head, or worse...block.

Anyway, what I wanted to suggest to you for flushing the cooling system after repair, is a marine bilge cleaner/water in a 50/50 mix. Run the engine up to temp, so the thermostat has opened and allowed the mix to circulate. Allow to cool so as not to get scalded when opening the cap, drain the system then add a 25/75 water mix... run the engine up to temp again and allow to cool. Drain again & refill with water. Repeat until the water drained is clear.

Engine oil, drained hot after the engine has ran for a while, should get most of the exchanged coolant out.

Change the oil & filter twice, run the truck & monitor the filler for any emulsification.

HTH.

Thanks Mickster.

I'll try that.

I thought in any case of filling the engine with diesel to the required level when done, then running the engine for a while to flush it from possible water.
I was still tinkering with how to clean the cooling system, as this had the engine oil through it mostly, you might just have provided the answer.
Do not really know what marine bilge cleaner is, but will try to find out.