It seems that every other XJ has a blown head gasket or run hot. I am just wondering if this is common else where and why it happens

 

A minimual cooling system that's not maintained for full efficiency. Never ignore the slightest hint of a cooling problem.

 

How can one determine a head gasket to be blown when he does not have a cylinder compression test kit? coolant in oil? smoke?

 

^the car stops running. The one bad head gasket I had years ago caused the car to stall out (no compression). It wouldn't restart due to the loss of compression. At the point, the compression test only verified what I knew had happened.

 

How many blown head gaskets are there? Same question for overheating. How many XJs are there on the roads, trails etc.

Don't forget that the ones you hear about are the ones posting on the forums who may have a problem. All the rest are driving around doing their thing. Of course there are plenty of owners who don't get on the forums and just go to their local shops.

I don't claim to have any statistics. I would like to know what they are just for fun but don't hold out a lot of hope.

 

I'd say there are few head gaskets but many with head cracks (especially with 2000-2001 models) and even more with rebuilt engines.

The rebuilt engines seem excessive to me. It seems like the only good reasons for a rebuild are broken piston skirt or hydro locked from off road adventure. Other reasons are owner neglect or mechanics encourage new engine when only head work is needed.

 

I think its because most of these engines have 200k+ miles on them and this becomes an issue with any vehicle with that kind of mileage. And also most of these vehicles are being used off road under harsh conditions too.

 

I'll second that. Not to ignore that the cooling system is not overbuilt at all, but when it's common to go well past 200K, things will fail. (including cooling system components). 280K on my original and she seems pretty sweet. Less than a qt/1000, and 22 highway MPG!

 

+1.
And despite all that, they still don't seem to pop their head gaskets all that easily.

 

Its mostly a lack of maintenance,How many of us know someone that drives a car forever does no maintenance and wonders why the car dies.

 

Whats your secret? I can only manage about 19 on the highway at best, and thats if I am going 10 under the speed limit.

 

Cooling system maintenance is really important. First thing I do when I buy a "new" old car is to change the oil, coolant, and every bit or rubber under the hood, by which I mean all the hoses and belts, including the heater hoses.

 

The newest possible XJ is now 13 years old, the oldest we commonly see on the forums is 27 years old.

Note we don't see very many V-6s or 2.5s on here.

There's not many vehicles that have that kind of longevity. Many are still being used as daily drivers.

This forum is where people land when they have a problem and do an internet search. I figure it's kind of like people who work in healthcare. Since all they see is sick people, it probably seems everyone in the world is sick.

There are plenty of other vehicles that overheat, and/or blow head gaskets. Since either a forum doesn't exist for them, or were're not on it, we're not aware of their problems.

 

Maintaince. When was the last time you flushed and changed your coolant?

 

There are no bad XJS, just irresponsible owners.