'91 4.0 engine tapping, problem or not?

[MtnForester]

Hi, I've found some good info on here regarding my Ranger so I thought I'd join up and see if I can get some advice regarding a potential Explorer purchase. I went back thru 6 pages of posts in the 4.0L section and saw several threads relating to the potential issue I'm looking at but wanted to run it by you guys to double check. One of my neighbors got laid off and wants to sell a '91 ExplorerXL 2dr 4x4 with the 4.0 and 5spd trans. It has 110,000 miles on it and he has owned it for about a year since purchasing it from the city. He let me take it home and drive it for the past couple days and the only issue I can come up with is that when you first start it up cold there is a constant loud TAP,TAP,TAP coming from the top of the engine that subsides after about 10 minutes of idling. Sometimes it will do it briefly after it's been driven and then parked for 30 minutes or so when you start it back up. I also noticed that occasionally while driving thru town at 35-45mph I will notice what sounds like the same noise but much quieter and in what I would call a rythmic or cyclic fasion like tap,tap,tap......tap,tap,tap......tap,tap,tap...He says it's been like that the whole time he's had it with no other problems. A friend suggested trying synthetic oil in it, so yesterday I put in some Valvoline SynPower 10w30 I had for my car and it seemed to make it louder so I drained that back out. I had a mechanic look at it today and he thinks it's the lifters bleeding down or something. I read some other posts here about maybe it could be pushrods or rockers? It sounds like it may be a common issue to these motors and I would like to know if this is something I will need to fix immediately or if it's a "they all do that, leave it alone" thing? The truck appears to have been very well maintained, including new factory radiator, alternator, and AC upgrade. There are no oil leaks on the engine block, not even any around the valve cover bolt areas which is a first for any Ford engine I've seen with any miles on it. So I really hate to have to crack open the engine if I don't have to. If the truck wasn't set up like I would have ordered it, 5sp, manual type 4x4, no pw/pdl, etc I would probably pass but I really like the truck and the $1500 price doesn't sound bad. Also is there a source for factory type replacement seatcovers? It's got the tan cloth 'striped' type and could use a new driver's seat cover. Many thanks for your suggestions and advice

 

[dogboy]

Yes, it is most likely the lifters. It is a common 4.0L issue.
Mine started doing it when I got the truck 2 years ago, and it has done it ever since.

If you feel very ambitious and want to rebuild the engine, then go for it, but I don't think it would be worth it at all!

As for the seat covers, I think you'd have to find something aftermarket, or replace the seats. I haven't seen any "factory styled" seat covers at all yet, but I haven't really been looking either. I'm not a fan of seat covers at all, I think think the make you feel like your moving in the seat, but that is just my opinion.

I hope that helps.

 

[MtnForester]

Hey thanks for the reply. How many miles have you put on yours with it like that? Wondering how much of an issue it is. As hard as it is for me to find a vehicle set up from the factory like I like anymore, this one is really a find for me. My money's tight right now and I'm trying to figure out if I could drive it for a while without doing any more damage than the cost of replacing the lifters and maybe pushrods at some point, but I'm not an engine expert. As far as the seat cover, yeah I'd be looking for a new or used factory style replacement. Not the aftermarket tie-on type that goes over the original seat, I don't like them either.

 

[dogboy]

The truck had 142K on it when I got it, it has 163K on the clock now.

So, about 21,000 miles and nothing has come of the problem, and I change the oil about every 5,000 mile with standard Castrol 10w-30. (I know I should probably change it more often than 5,000, but I just don't. I got more by every 6 months, than I do mileage)

All three of the 4.0L I've had/ driven have ticked to by the way. My Ranger (163K miles), the parts Explorer (243K, and the previous owner said it had done it for a long time), and the neighbor's Explorer also does it sometimes, but I'm not sure how many miles it has, I'd guess upper 100k's because it's on it's second tranny.

I think Explorers are about the only 4wd SUV that you can get with a manual. I'd be all over a manual 4wd, 5spd Explorer too if I were you!

 

[Beanmachine7000]

It'll more than likely tick like that until something else actually takes the engine out... It shouldn't really be worried about too much unless it has low oil pressure or it ticks ridiculously loudly...

 

[Beanmachine7000]

The truck had 142K on it when I got it, it has 163K on the clock now.

So, about 21,000 miles and nothing has come of the problem, and I change the oil about every 5,000 mile with standard Castrol 10w-30. (I know I should probably change it more often than 5,000, but I just don't. I got more by every 6 months, than I d mileage)

All three of the 4.0L I've had/ driven have ticked to by the way. My Ranger (163K miles), the parts Explorer (243K, and the previous owner said it had done it for a long time), and the neighbor's Explorer also does it sometimes, but I'm not sure how many miles it has, I'd guess upper 100k's because it's on it's second tranny.

I think Explorers are about the only 4wd SUV that you can get with a manual. I'd be all over a manual 4wd, 5spd Explorer too if I were you!

You can get a mid 90's 80 series Toyota Landcruiser with a 5-speed (and it comes from the factory with solid axles, and possibly lockers)... Too bad everyone wants an arm and a leg for them...

 

[MtnForester]

Thanks for the info. Oil pressure, by the factory gauge anyway, looks good. Engine still has lots of power, will spin tires if you mat it. I was thinking about fixing it if it was going to make the difference of making it last another 50k. If it could go 20k or more like it is then I guess I shouldn't worry about it right now. I just don't like noises other than exhaust rumbles from an engine. Bad thing is when I took it back this morning I noticed some spots on the driveway under the drivers seat area. Checked it out and looks like the brake proportioning valve sprang a leak. I'll have to see what one of those will cost or if I can fix that one. Regarding the Land Cruisers, I love those. My first 4x4 was a '76 FJ40, followed by a '7? FJ55 with "3 on the tree". Those were some serious machines.

 

[AaronC47]

Tapping noise

Just another thought here to the tapping, While I was in Vegas I had my truck there and the tapping was very noticeable when I first start it up, If I let it warm a bit it would fade a bit, and then Summer came along, I would start it up it would do it for a few minutes, and then I wouldnt hardly hear it all day again, I looked after I pulled motor and I had thought maybe the buildup in the oil galleys and various other places may have restricted the oil flow enough to allow tapping, and then in the summer heat I assume it would flow a bit better because of the heat, But that was just my assumption after pulling motor and taking a peek,

 

[MtnForester]

Well summer temps here may make it into the mid 70's so I don't know if that will make much difference. The guy that told me to try the synthetic oil was thinking along the lines that it would flow better, but as I found out that seemed to make the noise louder so I switched it back to regular 10w30.Waiting to hear back from the parts guy to see how much that brake valve is gonna cost to see if I can swing this deal.