INTRODUCTION
When a car's engine oil immediately discolours from its somewhat tan, or golden colour to blackish, are lot of things could contribute to that happening.

*** An already sludged valve train(comprising of the camshafts, valve stems, and even the valve baffles); and the oil sump(which houses the oil strainer, crankshaft main bearings, etc).

Such sludges or gel, are often as a result of accumulated oxidized additives in the oil, contaminants, and also metal shavings as a result of scrapping/scouring of piston rings with the interface of the cylinder walls.

It is these shavings, and the products of oxidation of the additives in the engine oils, that results in to engine seizures.

Sludge builds up with time.

It is difficult to fully dislodge an engine.
The easiest way, would be to dismantled the engine e, and do a thorough cleaning.

Such seizures could result in to any of the critical engine components failing.

Parts such as timing chains, guides, chain tensioner, valves and valve stems, etc.

*** Excessive fuel consumption, dumps too much of fuel into the combustion chamber.
For instance, if your car throws in a LEAN system trouble code, it depicts the car's ECU is commanding the pulse injection system rate to supply more fuel for to offset the deficiencies in the combustion chamber.

The excess fuel supply being demanded by the car's engine, is to keep the air/fuel ratio in the right proportion.


HOW CAN FUEL GET IN TO THE COMBUSTION CHAMBER?

1. When there's a distortion in the air/fuel ratio.
In a LEAN situation, which could be caused by manifold intact leaks, etc, the rate of fuel supply into the mix increases tremendously.

2. If there's faulty valves and valves stems.

3. If the timing setting is distorted. The engine e would work much more than required, thereby, the demand for fuel intake increases.

The timing of the valves are very important in controlling fuel economy, during the four strokes of an engine.

This is how it works. During the downward stroke(BDC-bottom dead centre), the intake valves opens, allowing in mixture of air/fuel in to the combustion chamber. As the pistons returns upwards toward the top(TDC-top dead centre), there's a build up of pressure, as a result of compressing the mixture. The compressed mixture of fuel/air ratio is then ignited by sparks from each of the ignition spark plugs, courtesy of the ignition coils (the power stroke). At this stage, the violent turbulence set by the combustion of the mixture translates that in to reciprocating motion, which then moves your car. As the cycle continues, exhaust gases are being expelled from the exhaust valves, and the processes continues that way.

So, when there's any disconnect between any of these processes, especially the intake stroke section, there'd be extreme temperature and fuel economy problems as well.


4. Procedural errors during a major engine work like replacement of camshafts bearing caps, etc.
Though such errors aren't common, but have being, due to my experience, some of the reasons an engine overworks, and dumps excess fuel in the combustion chamber.


CONCLUSION
The key to ensuring your car's recently replaced oil, doesn't immediately turn dark, is to ensure engine oils are replaced at as when due, use quality oils, and encourage your mechanic to be some more committed to replacing parts, such as valves, chain guides and timing chain, with more caution. The aim is for the mechanic to feel incompetent, but it's for both parties to save time, and resources. After all, you(the customer) is the one parting with your hard earned CASH!









CASE STUDY

CUSTOMER'S COMPLAINTS:

* I replaced the timing chain, timing chain guides, and 4Nos valves of my car, some two weeks ago, and ever since, I have observed the following with my car;

1. Engine oil immediately turns black after three days when I did an oil change.

2. The car consumes a lot of fuel. It wasn't like that before.

3. When the AC system is put on, the engine e overheats extremely. I don't use the AC system any longer.

4. The car can't ascend a hill. It kind if lose power approaching a hill.

4. Cylinder head gaskets has being replaced TWICE!

¶¶¶ Decided to try you, to see if you could fix the car.


CAR DETAILS

Vehicle type: Toyota corolla CE

Mileage: 89,589miles

4 Cylinder, 1.8L engine

Model year: 2001

Transmission: Automatic



TROUBLESHOOTING METHOD

1. We asked the customer questions, pertaining to the history of the car. This I mean, when did the problem actually started, and what solution has being proffered on the car from my colleagues.

This enabled us to really understand the customer, and be more emphatic on his plights.

The answer from the customer, was that it all started after the replacement if the timing chain and timing guide.

2. We got the car scanned for trouble codes, and freeze frame data.

The freeze frame data, would display AT WHAT CIRCUMSTANCES SUCH AS TEMPERATURES, RPM, SPEED, ETC, the fault occurred. That way, we won't be beating around the bush, trying to spend hours, figuring out what the cause could be.

It should be noted that scantools does not actually tell you where a fault is, but would only narrow down your search. Its somewhat synonymous to what a google search does.

It takes you through millions or even billions of search results of what you're looking for. Its now your responsibility to research through those contents, for the particular piece of information of interest to you.

The scanned results are as follows:

* P0115: Engine coolant temperature circuit malfunction (current code)

* P0171: System too lean(fuel trim). The codes are pending and current.

Freeze frame data(FFD): I purposely chose engine parameter for my baseline(692rpm)

P0420: Catalyst system efficiency below threshold(Bank 1) pending.

P1346: VVT sensor/camshaft position. sensor circuit range/performance problem (bank1) current code

P1349: VVT system malfunction (bank 1) pending and current.

FFD: 1250rpm

The scanning gave us some idea of where to commence the job.

From the scanned codes, and the complaints of the customer, that gave us further light into the troubleshooting.

We now knew that the problem was within the valve train area.

3. Car properly parked; jacked up and securely on a jack stand, for safety reasons.

4. Removed valve cover, to inspect the timing chain, and the intake and exhaust camshafts sprockets for any timing "jumps".





OUR DISCOVERIES

¶ Intake camshaft timing's jumped by two teeth.

A misaligned engine, would cause extreme temperature rise, excess fuel consumption, and even loss of power.

On extreme occasions, it would cause engine misfires, as a result of preignition and detonations.

¶ Radiator cap relieve valve spring had broken off; rubber seals also weak.
A broken relieve valve wouldn't function to regulate the pressures of the coolant in the radiator, during extreme temperature rises.

¶ Spark plugs weren't properly torqued.
This makes compression pressure to leak out of the cylinder head, during the compression stroke.

¶ Both intake and exhaust cap bearings were interchanged.

That was a huge mistake from the previous auto shop that fixed the car.

It should be noted that interchanging such critical components as those, who cause engine timing issues, and the uneven wear and tear of the camshafts beddings. There would also be¶ rattling noises that would come from the valve train area, immediately the engine is cranked.

VVT(Variable valve timing) sensor was already broken in the valve train portion of the intake camshaft.

Its important to note that the VVT works in consonance with a car's ECU, controlling when the valves are supposed to open, and close, for each of the strokes of cycle of operation of a petrol engine. It also controls power related operations of a car.

Since this sensor was broken, it wasn't sending signals from the intake camshaft VVT sprocket to the ECU any longer. That was the reason for the VVT related codes.
Honda, uses a VCM system.




THE FIX

1. Removed all the camshafts bearing cap bearings, and correctly fitted them where they should be. That's intake caps, going to the intake camshaft, while the exhaust bearing caps, foes to the exhaust camshaft.

Its very pertinent to apply some oil to the camshafts lobes and caps, to reduce scouring of the surfaces of cap bearings and camshafts.

2. The engine was properly timed, and valve cover and valve baffles washed with solvent(petrol). Main reason is to dislodge the valve train area of sludges, that could likely cause other problems to the engine in future.

3. Gave the engine a nice short, and it obeyed. What I mean is, I just stated the car, and it immediately fired up.

4. Replaced the VVT sensor with a known good one.

5. Replaced the stock fuel pump and the casing filter, completely from the tank, because the filter was terribly clogged, preventing the required flow of fuel pressure to the injection system.

6. Replaces the radiator cover to a 0.9 specification. The ratings on radiators, depicts the specific density of substance its supposed to work on (water).

7. Cleaned the spark plugs with with an iron brush, and torqued them properly.

8. Erased all the troubled codes, and did a drive cycle of the car to the island.

This was done in heavy traffic, with the AC system ON, to simulate the various conditions, according to my scanned data(freeze frame data), to observe the operation of the car, before handing over to the customer.

The vehicle was on 3rd mainland bridge from 05:15pm-07:30pm. That's to say, 2.5hrs, without any overheating, and so on.



The next time you've got an overheating and the oil in your car immediately turns black, know that it could be that excess fuel, and/or sludge is in the system.
Just drive it down for an inspections.
No fee charged for that.


PS: In case you've got an overheating issue, ensure all the basic components of the engine cooling system has being checked, before concluding its the cylinder head gasket that's the problem.

It pays to spend that small bucks on replacing a radiator, than to finally discover, it wasn't the cylinder head gasket that was the overheating culprit.







Regards,
Joseph
08066643532(WhatsApp/call)
Twitter: @dw_nig
oigonojoseph@yahoo.com

@Gazzuzz. That was the complaint from the client. That has being rectified after the repairs.

@Gazzuzz. OK na

my car oil turns black same day I change it. car has no codes. some cars just do that. well diesels do it for the fun of it. it doesn't mean an engine or oil is bad.

my car oil turns black same day I change it. car has no codes. some cars just do that. well diesels do it for the fun of it. it doesn't mean an engine or oil is bad. the second spark plug from left to right has a very nice tan colour. I don't think its fouled. that colour actually Indicates its burning petrol properly in that cylinder.

@9icetoo. If your car's engine oil turns black immediately an oil change, you might have;

1. A lot of blow-by of exhaust gases, going in the combustion chamber.

2. Another reason could be your car's internal engine components might be stocked with sludge, as a result of accumulated contaminants from the oxidation of the additives in the engine oil.

3. Some cars, like kia Sportage, 2007/8, I have worked on, immediately suffer such engine oil discolouration as I have said. In some of those instances, what I have noticed as the cause of the problem, has always being excessive fuel consumptions.

PS: Thanks for the corrections, about diesel engine.
The article was meant for petrol engine applications only.
I do understand diesel applications, immediately gets discoloured that way(black).

In summary, I think petrol engine applications with an immediate discoloured engine oil, tells you the engine might be a high mileage car, with lots of gel in it, or it has engine blow-by problems.

Spark plugs? Yeah, you're right. The other one with BLACK(soot) depicts excess fuel consumption, as we found out, and excessive electrode gap.

Like your contributions brother!

Please I seriously need help inrespect of my Toyota Corolla sport. 2008 model (Manual engine)

I changed my engine and as a result the ECU was affected.
I had to get another ECU which was converted to suite the new engine. After all was done, the engine was not compressing well and the fuel consumption was high and even smoking. The valve was then remove for grinding and the fuel injector been changed. The issue still persist. The ECU was then remove and tested in another car, and it worked perfectly.
I don't know where the problem is coming from. I need an expert advice.

Bros i hail. I drive a 2012 Honda Accord 4cylinder. Each time i start it in the morning it makes an engine rattling or roaring sound. The temperature around the engine area is hotter and higher than before. I have also not been satisfied with fuel consumption.