Ford 4.0 SOHC Timing Chain Problems – How to Avoid Them?

In 1997, Ford introduced a simple 4-liter SOHC engine for various models in its lineup. The previous OHV engine with the same displacement wasn't up-to-date anymore and it was actually very fuel-consuming, noisy, and unreliable. So, the company was hoping to improve basically all features of the engine and make it more economical with the help of head reconstruction.

Key features and my opinion about the engine

• Production years:1990-2010
• Average lifespan of 4.0L Cologne V6:230,000-260,000 miles
• Fuel supply type:port injection
• Power range:160-216 hp
• Fuel efficiency:awful
• Engine block material:cast-iron
• Engine reliability score:high
• The most common problems:very noisy work, timing chain issues, weak cylinder head, various leaks.

What's the Ford 4.0 SOHC engine? Is it good?

Actually, the engine is pretty good. It will not be the best engine in your life, but it's worth the money they wanted for it. Of course, now you can't buy new cars equipped with the 4-liter SOHC engine because it is considered outdated in terms of ecology and efficiency. The engine is pretty good, though, in terms of longevity.

It's not considered to be a problem-free unit. No, there are quite a lot of minor issues and complaints from owners. But still, we can say that most owners write good reviews and are glad that they have had some experience with the 4.0 SOHC.

Here are some important features you should know:

• these engines all have timing chains in their timing system which can be both good and bad depending on what you want from an engine;
• the V6 engine wasn't very powerful - it could have different power depending on the model it was installed in;
• overall, the engine was quite durable and reliable, but sometimes people say about its problems that were annoying;
• one of the most popular problems is the timing chain issue, and we'll be speaking about it in the next sections;
• also, the fuel consumption isn't considered to be the best side of this engine, that's why in 2010 it was discontinued in most cars;
• this engine was also used by Land Rover and Ford Australia, also Mazda used the 4.0 SOHC for its B4000 model;
• the engine has a very simple construction, but still, it has some technical issues that are hard to overlook.

We know that Mustang owners tend to say more bad things about this engine than, for example, Explorer owners, The reason is that the way to use this engine in Mustang is a little different. And eventually, the unit was engineered for the Explorer and the Ranger. It was meant to power big and heavy cars and deliver a lot of torque.

But in a Mustang, it had to deliver a lot of power, so Ford engineers had to work a little with the head construction and it appeared to be a bad idea because of longevity issues. But anyway, the 4-liter SOHC engine wasn't much worse in terms of reliability than any other Mustang engine.

Timing chain problems in a 4-liter SOHC engine

If you just say to a Ford fan "4.0 SOHC", he or she will immediately reply: Oh, this is that engine with a huge timing chain problem.

Yes, actually, this problem was a pain in the neck for nearly all owners. And it was one of the main reasons why this engine was discontinued relatively soon after it was presented. Engineers couldn't change the situation much and so the company just refused from this unit.

The main problems were as follows:

• chain guides breaking - this is a unique problem, no other engines with a timing chain could have these issues at such a low mileage;
• chain tensioners breaking - again, a tensioner in other cars should work for 100,000 miles or more, but in this vehicle, it could fail at 45,000 miles;
• valve problems - unfortunately, if you run this engine with tensioner problem for a long time, the engine will have problems with valves (bent valves and stuck head);
• other head problems - your engine may actually be blocked if the chain jumps because of the wrong tension and the heads may be just broken;
• unexpected chain jump - the problem that can kill your engine if you drive it at high RPM at this moment.

Unfortunately, a lot of owners have this problem and they actually can't do anything to prevent it. They can only hope that their engine is OK and it will not have this issue. The chain is said to go for more than 100,000 miles (if you read the maintenance guide by Ford) but it can only survive 45-50 thousand miles.

If you hear this engine rattling, you should just stop and never even start it before a specialist has a look. Because you can kill the engine if you keep driving the vehicle with a chain that has jumped.

Why does the timing chain problem occur?

Interestingly, the previous OHV 4-liter engines were OK and didn't have this problem. But somehow Ford made a mistake and they were producing these defective engines from 1997 up until 2003. In 2003, Ford engineers tried to deal with the problem but they weren't very successful. We know many Ford Mustang owners who also had problems with chains. As you know. The Mustang was equipped with this engine from 2005 till 2010.

The timing chain issue happens because of the production defect. But you can actually avoid any problems if you install the new OEM chain kit. It should be not just the chain, but also the tensioner and the guides. Sometimes, other parts will have to be replaced, too. And without this, you will not be able to drive your car for a lot of years.

These engines are now quite old and they all have potential problems with timing chains. You should be careful and if you hear the rattle, go to the specialists and deal with the situation.

Timing chain replacement costs for the 4.0 SOHC

When we tell people that their 4-liter SOHC is a good engine but it has this one little problem with the timing chain, they immediately ask us how much it is to replace the chain. So, we decided to investigate.

OEM timing chain kits will cost you a lot of money, we can't even say for sure because we haven't found any of them available for sale. But we think the price for the kit should be around $1,500.

The aftermarket kits will be less expensive. To be precise, you can buy a solid aftermarket kit for $900. But it will not be that durable and you will not get rid of the problem.

Also, you'll need to pay for labor. And this is a big part of your expenses because replacing the chain in a 4-liter SOHC by Ford is not that easy. The labor may be around $400 or more depending on a chosen company.

But it will cost you thousands of dollars to repair your engine if this chain eventually fails. So, don't try to economize in this situation.

Can you avoid problems with the chain?

Unfortunately, there is nothing you can do. One thing is the replacement of the chain kit. But even in this situation you never know how long this kit will work in your vehicle. Sometimes, the longevity of the kit is again 45,000 miles.

By the way, the engine itself will last about 230,000 miles with no other problems. But you will have to replace the timing chain, tensioner, and guides at least once during this time. And this is going to cost you a lot of money.

Here's when you should pay attention to the chain:

• the engine rattles when idling;
• it's hard to start the engine;
• significant loss of power is obvious;
• the engine stalls from time to time;
• the engine vibrates, not all cylinders work.

Noticed these symptoms? You should stop driving your vehicle and immediately go to the repair shop to have the engine investigated. The diagnostics will show what's wrong.

Final words

The Ford 4-liter SOHC engines are pretty hard to consider leaders in the class. They are not bad but the timing issues are important to remember. The timing issues are not only unexpected, but they are also very expensive to deal with. And we don't recommend driving a vehicle with a rattling engine or any other timing problems. Because this way you are risking your engine - it may be broken and it will be very expensive and hard to repair the heads.