Connect with us:  760-789-7470 OR 619-312-0456
M.D.S. Diesel Service Inc.
  • Our Shop
  • Our Work
  • Mobile Service
  • More...
    • MDS Jobs
    • About Us
    • Find Us

Fuel tank lining

1/21/2020

4 Comments

 
Is your truck 20 years old? Or older?
In trucks around 20 years old the fuel tank coating starts to degrade. Water content in diesel fuel makes condensation in the fuel  tank. Condensation in turn leads to rust in spots where tank coating is failing. Rust and fuel tank coating starts to clog fuel pickup tube. The metallic flakes can get into entire fuel system leading to failure of fuel sending unit, fuel pump, fuel filter, injector issues/ failure.

Symptoms can include:
low power, dying while driving, rough running, not making fuel pressure.

Repair consists of remove and repair tank, reinstall tank. Flush fuel lines, remove and replace pick up tube, fuel sending unit, fuel pump and fuel filter. Generally this takes 6-8 hours. The tank is sent out for repair and they will clean the tank and coat the interior with a gas tank sealant. The outside service is about a 2 day turn around for our shop.

Note***Tanks are no longer available on some trucks that are 20 years old so this is the only option. 
4 Comments

Weak Heater Core

12/10/2019

0 Comments

 

Blown head gaskets lead to a weakened heater core

You probably wouldn't think of your A/C and heater system needing attention when you are faced with blown head gaskets... 
But it makes sense if you think about the systems and how they work. 
The head gaskets seal the head to the block. The head gaskets also separate the combustion chamber from the water jackets in the head. The water jackets are passageways where the coolant travels through the head surrounding each cylinder. When the head gasket fails between the combustion chamber and the water jacket it causes combustion gasses (and pressure) to escape into the lower pressure cooling system. When the cooling system is over pressurized it causes the heater core to weaken and eventually leak. This will require the heater box to be removed for access to the heater core and AC evaporator. 
Picture
Ford head shown to illustrate the proximity of the water jackets to the combustion surface. 
​Unfortunately, this adds extra hours (12+) to a already costly repair. Dodge and Chevy units require the entire dash to be removed for access. Older american cars/trucks are much easier to access the heater core and/or AC evaporator. 

The heater core in this unit also shows evidence of calcification in the coolant tubes. The coolant should be a clear color coating the tubes, here you see a whitish tint. While you are changing the heater core be sure to inspect the AC evaporator. If it is face plugged that will lead to decreased airflow from cab AC vents. It is a good time to replace it if needed while you have the heater box out. 
Picture
0 Comments

Maintenance- Pre-trip Check

9/23/2019

0 Comments

 

The holidays are coming and that means traveling to the desert, family and friends, and vacation getaways....

Don't let your plans be spoiled at the last minute by vehicle repairs.
Look over your pickup truck, haul rig or motor home as soon as you plan your trip or up to six weeks prior. As busy  holiday weekends approach our shop schedule fills up with last minute repairs and previously scheduled work. Call us for inspections and repairs 3 weeks prior to your trip. Last minute delays due to back-ordered parts can ruin your perfectly planned vacation. 

Check out this simple list for a DIY inspection:
1. Time line-Complete a pre-trip vehicle check as soon as you plan your trip or up to six weeks prior.

2. Visual inspection- check your vehicle body for:
  • hanging panels
  • hanging mudflaps
  • loose trim
  • mirrors ok
  • tire wear and pressure
  • windshield condition
  • windshield wipers
  • Windshield washer fluid and spray function (make sure the spray nozzles are not clogged)
3.  Simple mechanical inspection:
  • headlights
  • brake lights and turn signals
  • Brake function and wear
  • horn function
  • engine oil level
  • transmission oil level (read your owners manual on how to properly check transmission oil)
  • generator oil level
  • radiator and cooling pack is clean and free of debris
  • Air filter- clean and properly secured
  • battery cables are securely attached and show no signs of corrosion
  • Dirt is cleaned off top of batteries (use commercially available battery cleaner spray, soap and water or baking soda paste. **NOTE** for baking soda- make sure it does not get into the battery or it will neutralize the whole battery)
  • House batteries on motor home are full of distilled water (if needed)
  • When was the last time you replaced hoses and belts? Standard recommendations list replacement every 4 years or 60,000 miles. If your vehicle does not get a lot of use go by the time line recommendation, not the mileage. Dry rot is a problem  for vehicles that sit.
  • Check for white crust around coolant hose connections
  • Wiring- do you notice any signs of rodent issues around your wiring harnesses or cab?
​4. Starting, running, driving. Take it on a drive! Check starting performance when it is cold and hot (turn off and start immediately).
5. Cranking should take 3 seconds or less. Longer crank times are indicators of possible oil or fuel issues. Call us to schedule an inspection.
0 Comments

7.3 Engine cover

5/11/2016

0 Comments

 

Cavitation can be a serious problem...

Picture
Cavitation is defined on Wikipedia as: The formation of vapour cavities in a liquid – i.e. small liquid-free zones ("bubbles" or "voids") – that are the consequence of forces acting upon the liquid. It usually occurs when a liquid is subjected to rapid changes of pressure that cause the formation of cavities where the pressure is relatively low. When subjected to higher pressure, the voids implode and can generate an intense shock wave. Cavitation is a significant cause of wear in some engineering contexts.

We had a customer bring in their 7.3 with a coolant leak on the front cover. Our mechanic was concerned it could be a cavitation issue. We have seen cavitation wipe out an entire engine. Thankfully, that was not the case for this customer.

The front cover showed minor signs of cavitation in the water pump mounting surface and the water pump impeller cavity. The oil cooler was found to be leaking at the seals and the exhaust manifolds had 2 broken bolts. The customer opted to have those repairs made as well while the engine was out. Taking care of all 3 items at the same time helped to save the customer on labor expense in the future.
Picture
Picture
Source credit: https://en.wikipedia.org/wiki/Cavitation

We have seen some extreme cooling package issues and

Proper coolant maintenance can go a long way...

Our shop recommends coolant flush every 2 years or 50,000 miles.
Ford sells a coolant additive that helps to reduce cavitation in the Super Duty.
Test strips are available to check the pH of your coolant. Improper pH creates a bigger risk for cavitation.
Remember when filling your coolant to use the proper ratio of water to antifreeze and use distilled water. Tap and well water can throw off your coolants pH.
If you ever find yourself in a situation where you must add tap or well water to your coolant, be sure to have your coolant completely flushed as soon as possible.
Remember to regularly check your coolant. Make sure to check only when your engine is completely cooled. A hot radiator cap can blow off and cause severe burns if checked when hot or under pressure.
0 Comments

Setting the overhead on a L10

5/6/2016

3 Comments

 

When an engine has all it's components in good working order

It makes any necessary repairs easy.

A Cummins L10 came in for injector replacement.

Injector replacements are, generally speaking, an easy repair. You remove all parts in the way of pulling and replacing the injector and re-install all good working parts as they were.

Not on a L10. When you are reinstalling parts the push tubes don't stay put on the rocker arms like other engines and have to be constantly reset to complete the injector install.
Once the injectors are all installed, after much sweat and swearing, it's time to run the overhead.
This is one of those steps that are made easier by the engine components being in good order to begin with. The overhead is set by matching timing marks up on an accessory pulley and the engine front cover.
Picture











This engine's accessory pulley is broken, so the timing marks must be found using a dial indicator.
Picture
Picture
This is a tool that is useful for mechanical engines, like the L10. The plunger of the dial indicator was set to rest on an injector rocker arm. The engine is then turned over by hand with a breaker bar.
The mechanic watches the dial indicator to see when the hand stops moving, or before the hand starts to travel in the opposite direction. When the hand stops moving is when the rocker arm is at Top Dead Center (TDC). Every time TDC is found, the mechanic makes not of it by checking which rocker arm is at the correct position and marking the pulley with a 1,2 & 3  OR A,B & C for a 6 cylinder engine.
Picture
3 Comments

6.0 STC fitting blowout

2/4/2015

5 Comments

 

Does your 6.0 have any of the following:

STC fittings
The fitting on the right is the stock OEM STC fitting, which is 2 pieces. The part on the left is the updated OEM fitting, a solid one piece part.
  •  Hard starting overnight
  • Rough start up
  • Long cranks when truck is hot

These are the symptoms of a blown or leaking STC fitting.
The difficult job for the owner of the truck is knowing if this fitting is the cause of your symptoms as this part shows no visible leaks when needing repair, the part is internal on top of engine.

The job of the STC fitting is to supply high pressure oil to injectors between high pressure pump and branch tube.
Most common result of blown STC fitting is no start. 3200 psi from pump can blow the original 2 piece fitting off.

If you're lucky and replace the fitting before
it leaves you stranded then t
he typical replacement of the STC fitting requires:
Remove turbo, intake manifold, remove high pressure oil pump cover, remove pump and fitting.
Replace STC fitting and align with installation tool.
Reinstall pump with new fitting.
Install manifold and turbo.

Usually our shop will charge 6-8 hours for this job alone. Our labor will include any other updates that are due in the same area, if they have not already been preformed. Other updates to consider for the 6.0 are
the turbo oil feed and drain line.

Replacement or reseal of oil cooler and oil pressure sending unit can add 1-2 hours of labor.


For this STC fitting job, the results were the exception.

A customers' 6.0 died at stoplight and wouldn’t start. The truck was towed in to MDS.
Mechanic hooked up our scan tool to diagnose no start. The oil pressure was not building to the minimum required starting pressure of 500psi.

Tore down top of engine and found STC fitting was blown. Really, really blown. So bad it left it's imprint on the rear cover of the engine.
STC imprint
You can see a crack in the cover to the left of the imprint
So, for this job MDS had to add some additional steps and quite a bit of labor to take care of this STC fitting.
Total time for this job was 19-20 hours on a 2 wheel drive Ford.

The transmission and flexplate had to be removed to gain access to the rear cover bolts to replace and reseal the cover.

4 wheel drive would add time to remove the additional drive shaft and transfer case.

Picture
What a normal rear cover looks like- no imprint!
Picture
View of rear of a 6.0 engine where the branch tube is situated
The original STC fitting went from 2 piece to a solid fitting. An early update added a metal bracket to the fitting. This has been sperceded by the one piece fitting.

Oil feed line originally had braided steel section and new line is solid metal pipe. Turbo drain is now larger for faster/non-restricted flow of oil
5 Comments

Ford fuel in oil system

8/29/2014

3 Comments

 

Some engine problems are sleeping giants...

Picture
And are difficult to diagnose with out some degree of engine tear down. A customer brought in his newly purchase used Ford 6.0 with some preventative maintenance and upgrades in mind. Once our mechanic started removing some of the accessories he discovered a messy problem.

Fuel in the Oil System

It's the only way to explain the shredded silicone gaskets, spotty oil and the tell-tale smell of diesel in the oil pan.
Picture
Shredded silicone gasket
Picture
A large piece of the gasket and small debris left on the block
Picture
oil screen in the main oil supply completely full of gasket debris and handle for screen expanded and disconnected from tray due to fuel
In many instances a pre-buy inspection can save you on some major repairs, but this truck would have required a very extensive inspection and testing to really catch the depth of this issue. 

This truck came in with no complaints to it's performance, the customer wanted to "bulletproof" the truck by doing the bulletproof oil cooler, new head gaskets and ARP head studs. If the customer hadn't been ready to do those upgrades it might have taken a while for these problems to make themselves known on their own.
Picture
side of block caked with oil
Picture
rear main seal leaking- likely because of fuel contamination
Picture
Fuel bubbles can be seen in waste oil bucket
Picture
Fuel contamination can be seen and smelled in oil pan
3 Comments

Starter wipes flywheel

6/27/2014

1 Comment

 
The customer called questioning why his starter made a grinding noise and a free spinning sound. He was encouraged to bring the truck in but it started on the 2nd try. Customer kept driving truck for a couple of weeks.
Eventually the flywheel stopped in exact same position and truck wouldn't start.

MDS pulled starter and noticed bendix gear was damaged. We looked into the flywheel housing and saw the flywheel had teeth chipped and that was why the starter couldn't grab
.

MDS replaced the starter, flywheel  with stock and  the flexplate was upgraded to a BD Duramax Flexplate.

Check out their website for the specs and benefits of this minimal upgrade:
http://www.dieselpowerproducts.com/p-7541-bd-billet-steel-flex-plate-01-12-gm-duramax.aspx?keyword=1041260
1 Comment

7.3 with leaking radiator overflow reservoir

3/25/2014

1 Comment

 
A customer brought in his Ford 7.3 Super Duty with diesel fuel in his cooling system. He had previously replaced his injector cups, but they were installed improperly. The correct tool to install the injector cups was not used, therefore the cups did not seat correctly. However, injector cups can crack and leak over time with normal wear and tear in any diesel engine. The cups were letting diesel fuel and coolant mix. Since the fuel system has a higher pressure than the cooling system the fuel was feeding into the radiator and it's reservoirs. The excess fluids were leaking out. This causes your fuel mileage to nose dive and over time can soften all the rubber surfaces in the engine. On this job we had to replace the o rings on the thermostat, water pump seals and all the engine hoses. If not discovered in time it can also damage the radiator seals.

When the engine is shut off the cooling system pressure exceeds that of the fuel system
and water can seep into your fuel filters and fuel tank. The water can cause rust and corrosion in the entire fuel system. For this customer we also replaced the fuel filters, drained and cleaned the fuel tank.

In the top left picture you can see part of a rubber seal that was being sucked into the injector.
In the top right picture you can see the fuel and water mixture inside the injector.
In the 2 above pictures you can see the fluid dripping into the injector cup (while the engine is running)
In this video clip the leak looks like a shadow moving across the top left section of the injector cup.
It's actually coolant dripping through the crack and into the injector cup.
It's easiest to see in full screen mode.

1 Comment

Ball Joint and axle seal replacement

2/7/2014

0 Comments

 

Did you hear that clunk?

It might be your ball joints. Part of normal wear-and-tear on your vehicle can include ball joints wearing out, but larger tires and off-road activity can lead to premature wear.
The inner axle seal was also leaking from the differential through the housing and the outer seal. You can see the oil spray in picture #2&3.
0 Comments
<<Previous

    The Shop Blog

    Here are some articles written by MDS about diesels, mechanic's life and what captures our attention.


    Picture

    Archives

    January 2020
    December 2019
    September 2019
    May 2016
    February 2015
    August 2014
    June 2014
    March 2014
    February 2014
    January 2014
    October 2013
    September 2013
    August 2013
    July 2013
    June 2013
    May 2013
    April 2013

    Picture
    Click on the link to take a survey for in-shop work.
    Picture
    Click on the link to take a survey for mobile work.
Powered by Create your own unique website with customizable templates.