Blown Head Gaskets on Land Rover V8 Engines

I've got a blown head gasket in my Land Rover.  What will it take to fix it?  That's a question Land Rover service managers hear fairly regularly.  We used to do head gasket jobs all the time, but in the last 5-7 years many of those jobs went bad. Many shops won't even do LR valve jobs anymore.  Why?

This is a big issue for people with the original LR-Buick aluminum V8 engine - all the US market Defenders and Range Rovers to 2002 and Discovery I and II models through 2004.

The engines overheated and failed either right after the head gasket job, or within a few months.  At first I thought the failures were comebacks - errors of workmanship.  But I soon realized the problem was not the workmanship - it was the motors themselves.  They were failing internally, in seemingly invisible ways.

Join me now as we look closely at a seemingly simple head gasket failure, and find there is much more to the story . . . 

This 2001 truck came into Robison Service a few days ago (early 2014) with a noise complaint.  Exhaust gases were blowing out between the head and the block.  It seemed like a classic case of fire ring failure in the head gasket.  In years past, I'd have been right on it with new head gaskets and a cleaned up heads.  Today, not so quick . . . As it happens, our caution turned out to be well founded.

Here are both heads off the motor.  As clearly shown, only one has a blowout (second cylinder from the left, upper head)  So far, it looks like a blown gasket.

OK, now lets look at a closeup of the failed cylinder in that upper head.  The blowout line is in the center.  Look at the holes for the head bolts.  The one on the left is actually facing the front of the engine, as you are seeing the head upside down (we will look at that hole in the block in a minute)   Note how its orange from coolant intrusion.  The one on the right (the rear bolt hole) is clear and that’s what you want to see.

The orange is sedimented Dex-cool.  Sedimentation is a known issue with Dex cool and it's particularly visible here.  It looks very different from freshly spilled coolant, like you get from teardown.  Scroll down the page four more images and you'll see freshly spilled coolant in a head bolt hole.  There's no mistaking the difference.

There are some motors where the head bolt holes go into the coolant galleries.  This isn't one of them.  These holes should be dry.  The fact that they are not suggests a crack or leak somewhere.

The blowout has damaged the head slightly but it's nothing we can't fix with a weld and resurfacing before the valve job.  Right now, that is the least of our worries.

Like I said, that dried coolant is a bad sign.  There are no coolant passages from block to head in the middle cylinders of a Rover-Buick V8.  There is no connection between the head bolt holes and the coolant galleries in the block, either. That area should never show coolant.  It's a bad sign, suggestive of internal failure.  But there's more . . . 

Now lets look at the block on the right side.

The blowout is clearly visible in the bottom of the second cylinder back.  Note the rectangular marks at the left and right edges of the block.  Those are the passages through which coolant flows into and out of the head.  There is no coolant flow through the middle.

The reddish spotting between 1-2 and 3-4 cylinders and the respective lower head bolt holes is even more suggestive of slow coolant leakage.  We will look at that in closeups.  When you look at the second and fourth head bolt holes from the left, those are dark.  The other holes are light, meaning no long term coolant intrusion.

This is a closeup of the lower head bolt hole and the edges of cylinders 1-2 on that side.  Note the pattern of leakage from the liners in toward the head bolt hole. See the “burnt” coolant in the bolt hole.  Those are sings of long term seepage.  This usually indicates a crack emanating from the bolt hole out to the liner faces on 1-2.  Also note the pattern of leakage continues onto the surface of the front piston, which is washed clean of carbon in the same area.  This is a sign of coolant intrusion into the cylinder and its location corresponds to the seepage on the block

For comparison here are the front and rear head bolt holes with a view up to the coolant passages from block to head.  In the rear one you clearly see some coolant leaked in disassembly and the difference between that and what’s dried and hardened in those inner bolt holes in the earlier images  is clear

Here is a top view of the blown head gasket.   There's no damage (other than the blowout) between this gasket and the head.  It's very clean and normal looking.

Closeup of the bottom reveals a different story on the engine block side.  That face makes the leakage pattern strikingly clear, and shows it’s all coming out of the block.  That's not surprising, because it can't come from the head.  There's no coolant in that area!  However, the area between the head bolt bore and the cylinder edges is hollowed out in the casting, for coolant flow.  That is the area that is vulnerable to cracking, and that's what's cracked in this motor.

The leakage traces on the bottom side of the head gasket really tell the story.  The way the gasket is discolored we know the leak has been developing over a long period of time.  What happens is that the crack grows, and as it does, the crack opening relieves the tension on the head bolt. That's probably one of the reasons the fire ring seal blew out.

Here’s a broader view of the bottom of the gasket, where two leaks are visible, to the left and right of the blown fire ring..  

Like I said, five years ago I'd have put head gaskets on this motor and sent it down the road.  And looking at today's evidence - it would have failed because the block was already damaged.  Head gasket leakage was a symptom of that failure, not the actual problem.  It may have lasted a week; it may have lasted six months.  Either way, it would have blown.

Here's a photo of a stripped engine block, after we cut it in half and circled the crack that made it fail.  The coolant passages are clearly visible

What do we do now?

The correct fix will involve removal of the liners, welding the cracks, and then fitting liners with flanges at the top, so that the liners will seal agains the head basket and coolant will not be able to go between block and liner and cause a blowout.

Read more about that in this article from 2012.

As a footnote to this story, when told about these issues, the owner of the truck told me he'd been adding coolant for a while for a period of months.  Now we know where it was going.  The coolant was getting burned in the cylinders as it leaked from the cracks behind the liners.  The fire ring blew out because the block cracks caused the head bolts to lose their clamping force.  We have an explanation for the whole thing, disagreeable as it may be to the one who has to pay the bill.  Still, I contend it's better to know the bad news up front than to discover it after a $3,000 valve job and head repair goes bad.

John Elder Robison is the manager of J E Robison Service, independent Land Rover specialists in Springfield, MA.  Find him online at www.robisonservice.com or on the phone at 413-785-1665

Should You Rebuild or Replace Your Land Rover V8?

That is the question facing more and more Discovery II owners as their engines age.  Land Rover’s Buick-designed aluminum V8 engines were never paragons of reliability; engines in the last P38 Range Rover and Discovery II models are arguably their worst.

There are three common failure modes.  Most common is the overheating failure, where the engine consumes coolant for a while and then overheats whenever it’s driven. Sometimes people fail to catch this in time, and the engine is driven till seizure.

Land Rover V8 with block failure behind the liner.  Coolant scours the piston clean

I've got several articles on liner failure online.  Here is the latest one.  This story explains the process in detail.

The next failure starts with oil pressure loss. The post-1998 oil pump is integrated into the front cover, and it’s prone to wear out over 100,000 miles.  If the pump merely wears you get low oil pressure, and a light at idle.  That can actually be fixed with a new front cover.  However, it’s often accompanied by worn main and rod bearings.  We’ve also seen the thrust faces break off the center mains, and either of those failures will necessitate engine overhaul.  If the pump actually fractures internally you can get total loss of pressure, and engine failure if the warning light is ignored.

The gear in this oil pump broke into pieces

The final failure is unacceptable motor knocking.  Sometimes this comes from lifters or rocker shafts but more often the noise is deeper inside - in the pistons.  We’ve also heard heavy noises from the lower end. The piston skirts wear and the motor starts knocking, first when cold and then all the time.  There’s no cure for this short of complete overhaul.

The only cure for excess piston skirt clearance is new pistons

It’s said that the production tooling had worn out but Rover continued to use it.  However it happened, the result was a series of engines whose internal clearances were at the wear limits before they even left the factory.  Internal balancing was abandoned to save costs, and finish quality dropped. Internal stress increased as the rated power was raised; first in 1999 and again in 2003.  The final straw was extra heat from leaner running; these motors were beyond their limits to achieve post-1997 emission compliance. 

Where the engines in older Rover models often went 200,000 miles or more, these final series motors seldom hit that mark. Most fail by 120,000 miles and a few don’t even reach 60,000. They seem to have gotten worse with age.

So what do you do about it?

Over the last decade, used Land Rover values have fallen and repair costs have risen.   Short block engines cost just $1,000 in 2004; by 2013 they were $6,000+ if you could find them. Long blocks - with the oil pump and heads - are closer to $8,000 Even so, the repair decision remains easy on a Defender, where vehicle values are usually above $50,000 and holding.  No sensible person would scrap a Defender for mere engine failure.  The situation is different for Range Rovers and Discoveries because those vehicles may be worth less than $10,000, and total repair costs can easily exceed that number.

If you’ve got a Rover whose engine is on its way out you basically have three choices:

• Scrap the truck;    
• Install a used motor;
• Rebuild your motor, or buy a rebuilt motor.

Some people will read this and ask, what about a different motor, a Chevy or Toyota conversion?  If you've got an old Rover, and you live in a place that does not have emission testing, that is an option. Unfortunately most 2000-newer Rovers in America are subject to emission test, many through the OBD port, and an engine conversion will not work for them.  Your conversion options are mostly applicable to 1995-older trucks without OBD II.  It's also worth noting that a high quality engine conversion is often 100+ hours of work, so there is no cost savings to this route if you pay to have the work done.

If the Discovery is “just a car” to you, the scrapyard option may look attractive; people in that position tend to move on to other brands of car.  Major repairs are what separate the serious enthusiasts from the weekend dilettantes.  The weasels get a can of gas and a match, and get ten grand from the insurance company.  A few good men take their own ten grand, and do a proper repair.  Then they go out and burn the gas, chasing action through backwoods and beaches. 

If you are dedicated to Land Rover, and like the separate frame/live axle design of these trucks, you know there is no present-day equivalent.  As an off-road platform the built-up Discovery II outperforms the Defender in many situations, with vasty improved civility and much greater family acceptability.  If you agree with all this, and your truck is in good shape otherwise, the most sensible option may well be repair.

That leaves you with a choice of engines.  I’m often asked about used motors for these trucks, and I am never in favor of that idea.  The reason:  any used motor you find is going to be 10 years old at least.  If its not worn out, it’s going to be well on the way.  Worst of all, any used motor is going to retain all the design flaws the motor you have now has, and it may blow up a month or two after installation.  When I look at the cost of used motors and the effort it takes to put them in I think you’d be nuts to choose that route.

If you’re still thinking about that notion, just remember that your late-series Land Rover V8 was a fatally flawed design.  What sense does it make to put another flawed motor in your rig?

To me, the only option that makes sense is the fitment of a flange-liner motor with a new front cover; one where the late series design deficiencies have been addressed.  That is the solution that leads to long term reliability.

I’ve written several articles about the use of flanged liners to fix overheating in these engines.  When that technique is combined with new pistons and an updated front cover, and the motor is blueprinted and balanced you end up with a rugged and smooth running engine that will last a long time. 

A rebuilt Rover engine, ready to install

Robison Service has been rebuilding engines like that for several years; it’s the only way we do Land Rover V8 motors now.  Other companies in the UK and the USA are offering engines with various combinations of parts and technology.  In my opinion that is the way to go.

There are still a few “old style” short blocks in the market with the original Land Rover tube liners.  I suggest avoiding those motors as they have all the flaws of the original engines.

Now for the final question:  What will it cost:

*** SPRING 2016 UPDATE: The total cost, parts and labor, to rebuild one of these Land Rover V8 motors, including removal, teardown, overhaul and refit; fit flanged liners, and do all the other work that's typically needed runs $12-15,000.  It's a significant commitment and there are no good shortcuts.  ***

A set of pistons, flanged liners, bearings, and other parts to rebuild a short block will run a bit more than $3,000.  The machine work to rebuild a short block is substantial.  Here is what we do in our shop:

• ·      Tank clean and bead blast the block
• ·      Remove the old liners and check for cracks
• ·      Repair the cracks
• ·      Check the block for straightness, corrosion, and other damage
• ·      Machine the block to accept flanged liners, and install the liners
• ·      Bore liners to match the new pistons
• ·      Rebuild crank and rods
• ·      Line bore block if needed; deck cylinder head surfaces;
• ·      Balance rotating mass
• ·      Assemble short block

We can change displacement from 4.0 to 4.6, or something a bit larger.  Upgrade costs can be anything from $1,200 up.  Other shops may follow different steps, or a subset of these steps.  Not all blocks are rebuildable; a few are too damaged from overheating.  Expect the total cost for a rebuilt short block to be in the $5,000-6,500 range; more for custom work.  You can rebuild the block you have (that's what we do most of the time) or you can buy an exchange block, already built.  

Then you get into the rest of the job . . . 

Add a couple thousand more to rebuild the heads, replace the front cover and take care of the other rebuilding work.  That gives you what rebuilders call a "long block" - a complete motor less the covers, accessories, brackets, hoses and wiring.  Those too can be purchased or made.

A wise owner looks at the ancillary items – things that should be attended to when the motor is out. New water pump, hoses, motor mounts are just a few possibilities.  You may need a radiator, or AC work, or a steering box and lines.  Those costs should be added in for a first-rate job.  You should also consider cosmetics - do you care how the engine bay looks?  If you do, this is the time to refinish or re-plate under hood pieces while they are all out and apart.  The change may be striking:

A restored D90 engine bay

Finally there is the labor to do the job; expect this work to consume 30-40 hours at whatever labor rate prevails in your area; more if you get into detailing or custom work.  Jobs like this typically cost $11-14,000 in my part of the country, as of fall 2014.

It’s expensive, for sure, but it’s the only repair that’s going to last.  If you have a Rover V8 and you want to preserve it I suggest giving this plan serious consideration.

1995 Range Rover Classic atop Killington Mountain

Note:  The advice in this article applies to any 1987-newer Land Rover with V8 engine.  If you have a pre-1999 engine you may not need the flanged liners but the rest of the job is essentially the same.  Owners of older cars should also consider a diesel conversion, something that is not possible for those of us with newer vehicles in states where emission testing is a requirement.

Here are three articles about internal problems in the V8s:

V8 engine failures - slipped liners and more - from 2009

Should you rebuild a failed Land Rover motor? I have an article about that situation here that covers the decision process

What's the latest on top hat or flanged liners? This article tells all you want to know about the flanged liner overhaul

Discovery II models also have a problem with frame rust.  We first began to see this in the spring of 2014, when we saw several trucks whose rear frames rusted right through over the winter.  These vehicles seemed more vulnerable to rust than the earlier models.  Read this article to find out why, and what you can do about it.

Are you thinking of restoring a Land Rover?  This article shows some of what's involved.  This article explains the difference between repair and restoration, two very different processes.

If you drive a Range Rover Sport or LR3, read this story on differential failures

And if your supercharged Rover is losing power - read this

Programming keys for your Land Rover is here

(c) J E Robison Service

John Elder Robison is the founder of J E Robison Service, independent Land Rover specialists in Springfield Massachusetts.  John has been part of the Land Rover community for 28 years; since the marque’s 1987 return to North America.