Overworked/failing u-joint causing increased engine temps?

Hey all. I installed a set of 4" lowering blocks in place of my 3" ones to get the ass end of my wagon down a little bit more last week. Took it around the block a few times, etc. All seemed well until tonight when I went on a cruise night and put about 60 miles total on the odometer.

It was about 90* outside when we left. Engine seemed to be working a little harder on the freeway driving down, ran warmer than normal and the temp gauge was pegged about halfway down the cruise strip. I pulled into the nearest parking lot and let her cool down. Topped off with water about an hour later but the coolant level wasn't very low to begin with. Left to go back home and it was about 70* out. Engine ran warm again coming home and it took a few freeway miles to get the cool air working its magic inside the engine compartment (holes in the firewall keep me aware of underhood temps!). Engine still felt like it was working harder than normal. Pulled onto my street and I could hear a faint squeaking in the rear. It wasn't the brakes because the sound could be heard while applying brakes, going forwards and reverse, etc. I think it's the U-joint that I screwed up by putting the 4" blocks on.

Here's the blocks I put on from Summit. http://www.summitracing.com/parts/djm-sb2400-4/overview/
They have a bevel in them to compensate for driveshaft angle. I didn't measure the driveshaft angle after install as I figured seat of the pants would tell me if there was a major problem. Totally should have measured while I was under there.

I guess my question is could an increase in driveshaft angle have made the engine work that much harder for me to notice or is there something else that coincidentally occurred?

Thanks all, NAES

 

Pix. How old/maintenance of the U-joint. Is the drive shaft bottomed out at the trans? Or near so, when it hits bumps the drive shaft moves forward.

 

Spicer U joint is less than 2 years old. Drive shaft is about 1 1/2" from the output shaft so there's no bottoming out.

I'll get under it this week and see what's doing.

NAES

 

I would guess that if your ujoint were binding enough to cause that much drag on the engine you'd definitely know. The thing would be howling like a banshee and probably get red hot

 

How about at the back end, from experience the driveshaft usually rubs at the back end of the driveshaft tunnel if it is going to rub at all. That usually causes a nice shiny ring around the driveshaft in that spot and on the spot it is rubbing on.

To add to that a lot of lowered rides won't have the driveshaft rub the tunnel with just the driver and no load in the back but add a couple of passengers and a cooler and a couple of lawn chairs and all the sudden the back end gets just enough lower to rub at times.

On the overheating, I'd also check to make sure that the radiator is clear of bugs and dirt so air can flow through along with making sure the fan is working if you have a clutch fan.

 

First confirm your perceived heating issue is not something else like a temp gauge that is misreading. Second make sure your advances are working in the dist. Advance not working correctly would give both symptoms you have.

 

Don't you guys think that if the driveshaft were rubbing on the tunnel that it would be overly obvious that something was wrong ?
As in HOLY SHIT what the fuck is that!! kind of obvious.
Let alone enough to make the engine work harder.

One little zip tie on a driveshaft will get you thinking the car is falling apart !!!

If a ujoint were to blame for this phenomenon it wouldn't be a question what was causing it.

 

Bit of a stretch, but maybe the lowering has blocked off the airflow under the car?

 

The U-joints are not causing your engine to run hotter. What is probably happening , While the air is being scooped it is building pressure under your car causing air to slow and find another route...

Like the Myth busters test regarding air flow with a cover over your bed, tail gate up and on with no cover, and no tail gate..... Its the same principle....

I am with R Rope on this one

 

Sometime later we will get the rest of the story on this one. My guess is that The now missing part of the story involved some under hood work near the distributor.

 

He also hears a faint squeak........so it more than the heating issue popping up after the modification. Try some decaf.

 

Got under it today finally and swapped the 4" blocks for 3" blocks. The pinion angle with the 4" blocks was off by around 5*-7* from the trans output shaft face. Not good at all. The 3" blocks keep them dialed in to one another.

Now I still have the same growly/squeaky thing going on and the rear end sounds like it takes a hit with a BFH during 1-2 upshift and when letting off the throttle after moderate acceleration. I'm thinking the increased pinion angle and subsequent stress over the last outing must have screwed up the rear end. I'm not sure how to check/test it without pulling the entire rear end out. Any thoughts on this one?

Just to be clear, the single and only thing that I did to the wagon was switch to 4" blocks in the rear, nothing else. I don't think that 1" made any difference as far as air escaping or being trapped somehow. The driveshaft tunnel has been raised already and I'm very, very familiar with the nasty sounds that makes. Temp gauge is one of those ether/mechanical ones that connects directly to a coolant fitting in the intake manifold. Radiator is about 2 years old since rebuild. Car ran great from SoCal to Vegas about a month ago. Just tooling around town since, no major drives since then. Sticking thermostat maybe?

Thanks for the help guys, what do I check next?
NAES

 

Something to think about. In 1997 I bought a brand new Ford Dually and had it lowered with a commercially available kit. I was coming back from Bike week in Daytona towing a 26' trailer full of bikes when the check Engine light came on and the temp gauge shot way up. I stopped and heard what sounded like coffee brewing coming from the rear end. I ate a Big Mac and waited about an hour and all was fine. Got up to speed and it happened again. the rest of the trip makes for a good and long stroy, but the bottom line was the lowering kit was designed incorrectly and was pointing the front of the diff too high starving the Pinion bearing at speed which got the rear end so hot that the driveshaft transmitted the heat to the trans which then overheated it and the motor!
Shimming the rear end to get the pinion angle right (after a comedy of errors at the Ford dealer who replaced the entire rear axle assembly first, and Dana 70 dually rear ends are Not cheap) fixed all the problems!

 

2 weeks ago I had a 4x4 f 150 with the pinion bearings so far gone it was ridiculous !
Low pitch loud growl on acceleration , quite on let off.
The pinion was bouncing around like a hot dog down a hallway when ran on stands.
This caused no drivability issues with the engine.

Today I did a GM 10 bolt with a horrible growl that I couldn't pin point exactly. It was making all sorts of racket and the standard diagnosis was inconclusive.
So what did I find ? Pitted and egg shaped axle, slightly worn opposite axle, pitted carrier bearings x 2 carrier flopping around, pitted pinion bearings x 2 and some lash in those bearings and sloppy gauled spider gear surfaces .
Pretty much toast and still no drivability issues. Aggravating noises yes.

The bearings weren't welded together they were worn and pitted.
This isn't no little faint squeak- this is major noises

 

Get in touch with your local driveline shop for details, but I remember that a drive line is made to handle only so many degrees at the joint....anything over that has a formula for power loss...for every degree over the norm represents a number of horsepower it take just to turn the shaft. You may try a cheap wedgie under the diff to correct the angle of the dangle. Still question the overheating unless your system is up to the wall already. how about that thermostat?? Make sure your lower hose isn't collapsing when you rev it up...if your running a low pressure system like 4 to 7 lbs you may need a spring in the lower hose to keep it round. High pres. like 14 to 18 lbs seldom need a spring. Let us know what you find !! flop

 

You did the right thing switching the blocks back, but I may have missed it, do you still have the overheat issue after switching back?

As for the rear end, is it open or posi? I had an issue with the clutch pack of a 10 bolt gov-lock blowing up. All that trash floating around made for very great effort in moving the truck, but caused no heat issues.

You might try jacking rear end up while in neutral, then turn tire by hand. If it feels resistant, maybe pull cover and have a look. Can't hurt.

Good luck.

 

Thanks again everyone for the replies.

I switched lowering blocks but only took it around the block a few times. The scraping/grinding and ridiculous shift noises sent me home pretty quickly.

Currently with the 3" blocks, the pinion angles are correct. With the 4" they were totally off by around 6*.

Coolant hoses are all made for a higher pressure system so I'm doubtful that they are collapsing under pressure. Still haven't gotten to the thermostat yet. That idea dawned on me only today.

Diff is from a 68 Mustang and I assume it's an open diff. No cover for me to remove and inspect stuff. I have to remove the driveshaft and take the front of the diff off. I'm really feeling like I have toasted this rear end. I'll run it over to a shop in the near future and see what a second or third opinion is.

Man this sucks. Car has run flawlessly since I got her on the road. But as I once heard, "old car, new problems".

I'll keep y'all posted. NAES

 

Why not park it on level ground put in neutral and see if you can push it?
If something where binding/ dragging that bad you wouldn't be able to budge it.

 

OK, the general consensus is that the rear end needs to be opened up and rebuilt. Most likely the increased pinion angle was the final nail in the coffin for an already failing pinion bearing.

So now the million dollar (well actually thousand dollar) question is, do I pay a pro to rebuild it or do I go ahead and take on this challenge myself as I have with the rest of the build?

I don't really have a thousand bucks to throw at the rear end right now and if I can go ahead and do it myself then I'm all in. I did a few googles on the subject and it seems straight forward enough. Am I kidding myself here? There might be a few special tools to buy but I'm OK with that.

Lemme know your thoughts guys, NAES

 

$1000.00 ? ?
This is a ford 8" or 9" right ? ( 68 mustang with no cover are the clues I got )

You can get an open chunk to drop in it for less than 200.00. Less out of pull a part.
You can get a LSD for about 4 ish.
You can get a rebuilt locker with your choice of new gears for about 8-900 ish.

That's all bolt in stuff on those rears. You just need to know your spline count on the axles before you jump off and buy it.

You can buy the new bearing kit for about 100ish. That should come with both pinion bearings, races and seal and both carrier bearings and races crush collar and probably a bunch of shims.
Here's the trick, if you DO NOT need/want to change the ring and pinion gears this is also a straight forward swap. Eazy peazy. You'll need to press the bearings on and off but there's a lot of places that will do it for you. Keep everything separated left and right and keep the shim behind the pinion and replace everything EXACTLY as it was removed. Re set the old crush collar at zero lash (0 lash very important and there is no backing up) and 99.5% of the time you are done. Check the gear pattern and see. If the gear mesh pattern is off you'll need to think about why and probably need to redo the crush collar.
If you've never ever done this before you can do it in a weekend if you can get the bearings pressed on Saturday. Second one will take you 3-4 hours, get a few under your belt and it will down to couple hrs if the brakes don't give you any troubles.



If you want to change gears it's a dance for the trained.

 

Awesome! That's pretty much all I needed to let me know I can tackle this one, at least the first part of it all. Thanks so much for the info.

Yes, the price was in the neighborhood of a grand to do the job. And that was me bringing in the rear end removed from the wagon already.

It is a Ford 8", sorry I didn't mention it. If it's that straight forward then I'll do some more reading/researching on the how-to's of it all and get to work.

I was thinking about going to a higher gear ratio if the R&P are bad. Obviously then I'll be in over my head and have to get a little help on in.

Thanks again, NAES

 

In my overheating experiences, ambient temperature made all the difference. I had a comet that would run fine in 90 degree weather, but peg the temp gave at 95 degrees. Speed also makes a difference. Too fast or too slow would make overheating issues worse. Consider those before blaming the u-joint angle. Crazier things have happened, but your original question is kind of like wondering if my car is overheating, because my girlfriend is overweight. Neither are ideal, but the system should be robust w ought so that one misfortune does not cause the other.

 

^^^^^ Too funny but a good point. I went back to the original setup and the rear end now growls and groans. It definitely has a problem.

Engine temps have never been an issue. I went to Viva from SoCal in similar weather and for a much longer distance without a single issue. I'm convinced the rear end is on its way out.

NAES