How long can I drive with a wobbly harmonic balancer before it throws the ring?

[N8N_99xj]

This morning I got to work and it was dark so I quick aimed the fog lights that I just installed in the parking lot. I did hear a slight knock so I was hoping it was the alternator as I was going to replace it anyway. When I left I popped the hood, didn't hear the knock anymore but I did see there's a pretty good wobble on the balancer, maybe 1/4" or so. How far can I drive it? I'm assuming the answer is "straight to the shop". Gonna call tomorrow and see if the dude will replace the alternator and fan clutch at the same time as I already have those parts but I don't think I wanna do the balancer at teh side of the road.

thanks for any advice!

 

[Anak]

A subjective measure of a quarter inch or so does not alarm me. The precision with which many balancers are made is underwhelming at best.

More importantly, in what condition is the rubber? Yes, I know, you probably can't get a good look at it. Use a mirror and a flashlight. Or go high tech and take some pics of it with your phone (one of the few actual uses of the cursed things). Are there chunks missing? Or is the rubber hanging out of balancer? If yes, then yes, this is high priority. If there are just some cracks in the rubber then you are in the same boat as most other 30 year old vehicles.

Another way to asses the situation is to try to move the outer ring of the balancer. If you can move it relative to the inner ring, then yes, you need to do something ASAP, but if it is solidly adhered then you do not have an urgent situation.

You probably are indeed due to replace your balancer, especially if it is the original balancer, but it doesn't have to be an emergency job.

If your XJ is typical of what is out there you probably are also due to replace the crank seal, timing chain and chain snubber as well. If it were me I would order the parts and take care of the whole shebang in one swell foop.

 

[75SV1]

It's not the rings, I'd be worried about. Its the main bearings. Mine took out the main thrust bearing. A harmonic balance is about $50-70. I don't know what the labor would be.

 

[Unclewolverine]

On my 6.5 diesel the second the balancer failed, the crank broke. So, when I saw my rubber was looking rough on my 4.0 balancer I went ahead and ordered a new one. In the mean time I put a scribe mark between the two rings and when they moved apart indicating rotation of the outer ring, I replaced it. It's not something I'd let go very long.

 

[N8N_99xj]

It's not the rings, I'd be worried about. Its the main bearings. Mine took out the main thrust bearing. A harmonic balance is about $50-70. I don't know what the labor would be.

I meant the ring on the balancer coming off the hub, I've seen videos of that happening, including on XJs. I don't really want that to happen...

 

[Anak]

I meant the ring on the balancer coming off the hub, I've seen videos of that happening, including on XJs. I don't really want that to happen...

Yes, that is the danger.

As long as the rubber is all still in there it is not likely to come off right away. That is why I say look for missing chunks or pieces hanging out of the balancer.

Cracks in the rubber are the stage which will lead to missing chunks/pieces hanging out. But it can take a while to go from one stage to the next.

 

[75SV1]

Put a white stripe crossing the hub and the ring. If that shifts, then it needs replaced. It might take a while for it to fly off. Its that it might be doing damage. They are not that expensive and the labor to do it yourself is not that time consuming.

 

[lawsoncl]

I couldn't find the video again. It was from an auto shop that the customer brought a truck in for a bad engine vibration. Parking lot video showed the mechanic goes out and starts it, there is a bang, the balancer falls out and runs across the parking lot.

If you have 1/4" runout, the belt will likely let loose first.

 

[THE2NDXJ]

Its easy to replace and inexpensive, so do it sooner than later. Replaced my wifes recently. For straight-shot access, remove the bumper, grind away a tiny bit of metal from the lower support that hangs down in front of the crankshaft nose bolt, and blast it off with an impact. Summit has some good American made ones.

 

[N8N_99xj]

So I threw in the towel, took the day off work today and took it to my friendly (sort of) local BYOP friendly shop, had them replace balancer, alternator, fan clutch, fan shroud, and thermostat. Was under $700 including them providing the balancer and a new crank seal so I'll take it for peace of mind. Got there at 7:40 and they were done by noon. Bonus: got to eat lunch at a Korean restaurant I hadn't been to in a while, and caught up on my reading.

Gonna be nice to have heat next cool morning, we'll see when it's hot if the clutch/shroud fix the "hot when it's hot" problem. It'd better as the water pump and rad look new so I dunno what else to replace

 

[75SV1]

'Gonna be nice to have heat next cool morning, we'll see when it's hot if the clutch/shroud fix the "hot when it's hot" problem. It'd better as the water pump and rad look new so I dunno what else to replace '
Thermostat. I've had one 'fail open' and one just came apart. So, the radiator fluid doesn't get to temp on cold days.

 

[N8N_99xj]

'Gonna be nice to have heat next cool morning, we'll see when it's hot if the clutch/shroud fix the "hot when it's hot" problem. It'd better as the water pump and rad look new so I dunno what else to replace '
Thermostat. I've had one 'fail open' and one just came apart. So, the radiator fluid doesn't get to temp on cold days.

Yeah the quality hasn't been good. Have had to replace thermostat on the last three vehicles I've purchased, all XJs. First two replaced were Stant and I don't know about the third because someone else did it. First one just didn't have the tight temp control I wanted, the temp gauge would swing back and forth while driving. Second one stuck closed while my friend was driving (he didn't like it when I told him to turn the heater on in NoVA on an 80F day) and this one either was stuck part open or someone tried to mask a fan issue with a 160F thermostat. Meanwhile the original on my 2002 GTI got lazy just last year and the original in my 2009 BMW is still kicking.

I've used Robert Shaw thermostats (now sold by Flow Kooler) in all three XJs and they've been rock solid so that's my recommendation. First one was back when they were still USA made and 2nd and 3rd were Chinese but the quality seems to still be there. This one shot right up to a tick below 210 when I left the shop and stayed there the whole way home (about 25 miles, mixed highway and surface streets). Used to run cold when cold and hot when hot (would heat up until the e-fan kicked on) am hoping I've fixed everything. Also will be nice to not have the voltage drop at stop lights with my lights on (and they're all LEDs except the turn signals) and of course not worry about the balancer ring yeeting itself...

Now I'm thinking I should have replaced the tensioner as well but hey, the belt's been off so that should be a curbside job if necessary.

I told the shop guy, this is the nicest XJ I've ever owned and at the same time has needed the most work.

 

[N8N_99xj]

So I'm feeling good about all that work, it suddenly got hot and coming home from work I had the AC on 3 and even at a painfully long light it was right at 210.

Using the AC really highlights the need for new engine mounts however. It's on the list, along with new cats...

 

[75SV1]

Also, if you have an auto trans, then a trans cooler should help. Some of my XJs run around 205 to 210. At that temp it doesn't concern me. If 215, then I start to worry. 220, then I'm pulling over.

 

[N8N_99xj]

yeah 205 to 210 is normal IME (this is my third XJ) and that's where I'm at right now. In the last few days I've experienced both cool mornings and 80+ degree weather and things are much more like I expect. I don't even think I've heard the e-fan come on except for once when it was about 82 degrees, I had the AC on, and was sitting at a light for what felt like 10 minutes (it might have been 5, it was a very long light) and the needle was rock solid at 210. I could also hear the mechanical fan when it got hot which I couldn't before. I also have left my house when it's ~40F and had heat within two miles which I didn't before, so I'm going with both the thermostat and the fan clutch needed to be replaced, but between that and the fact that I appear to have a new water pump and radiator things are good now.