Got a call from a friend with a 99 XK8 with his AC not working & engine overheating. Picked up a belt from pep boys & went to meet him. His engine was too hot to touch even after a good 45 minutes after it came to a halt!

Looks like the idler pulley (next to the alternator) bearing had failed & thrown the belt (Took me an hour to dig the belt out the engine). The bolt depicted in the picture & the 2 rings (outer & inner bearing housings) are what left of the pulley & its bolt!

This lead to extreme overheating that ruptured the expansion tank & loss of most of the coolant!

Towing the car to the shop i started with a compression test thinking head gaskets at worst but am greeted with a big fat ZERO, 0, nada, nil, nothing compression in ALL cylinders. Used 2 gauges to make sure & tested each cylinder multiple times! Just to make sure, took out all plugs & still "nothing" when cranking the engine!

Tough break for my friend all over a bearing!!

 

Well how long did he cruise along with the belt gone if he only ever noticed "his AC not working & engine overheating"? No squealing? Steam pouring out?

That may be a nikasil block. If so, the overheat may have burned off the oil on the cylinder walls and so it is not sealing. Try again after squirting some oil in each bore. You wouldn't lose compression on every cylinder of an 8 cylinder motor at the same time.

 

+1 on #2. No compression on all cylinders is very difficult to imagine.

Suggest reading through the archives for Nickasil info and cylinder washing.

Don't give up the ghost yet.

 

He was going a steady 75 for a good 10 minutes after he lost the belt. No reports of steam but evidence of plenty of coolant covering the engine bay & drivers side front fender. compression in all 8! im certain. will check again after oil trick.


No compression is also perplexing to me as ive never seen it first hand but im certain of it. I checked & checked again in all cylinders with 2 compression testers as i also was finding it hard to believe. I wont giver up yet.

 

The valve seats often drop and bend valves when abused/overheated like that. 10 minutes with no water circulation? Tough to say over the internet....but if I were a bettin' man, I'd say the engine is done. Your buddy should have pulled over as soon as he noticed the issue.

 

I will pull the heads & post up.

 

Might try a leakdown to see where you are losing it first. Pop the cam covers off and look at the valve clearances, that will give you a quick answer about the valves being bent.

 

Why would you do all that labor, except for our entertainment?
Even if you did get some compression back, this engine is majorly jeopardized and will no longer be usable.

 

The bearing "Failed".
The Fookin driver toasted the engine!!

 

I was not going to say that . . .

 

Righthand, tell your friend to look on the bright side........ I,ll buy the cigar lighter off him....... if it.s not fooked that is!

 

We'll do & post up.

 

Point taken.

 

i have read that the 99 can take the newer engine just fine. search the forum for ideas on how to get a good used one.

 

this salvage looks good. xk8 items - Get great deals on STRUT, SEAT items on eBay Stores!

 

Car-Part.com--Used Auto Parts Market

 

Performing a leakdown & valve clearances tests gave negative results so i pulled the heads. They are at the machine shop where im getting a quote for new valve seats only on the ones that came off, new valves to replace the bent ones' resurfacing etc.. etc...Some of the pistons have been stamped pretty good by the valves but it looks cosmetic & cylinder walls look fine...

 

As soon as the belt broke he would have gotten an alternator light followed by various other lights and warnings as the engine overheated. Did he just cross his fingers and hope everything would be OK if he ignored all of the warnings?

 

I think the tough break came when he drove the car after it was obviously overheating.

Great job in keeping at the problem and not getting discouraged though. I might have given up too early!

 

^this.

If he would have pulled over quickly after the incident, the repair bill might have only been as bad as a the price of a tow.