Piston Slap: Aluminum is Not One of El Dorado's Lost Treasures

Sajeev Mehta
by Sajeev Mehta

SQ writes:

Hello, I am a young female looking to buy a car in a few weeks. I’m in love with Cadillacs & was wondering which years of Cadillac Eldorados have aluminum around the engine? I have been researching this for weeks and have not found any information. Could you please help me out with this?

I would greatly appreciate it. Thank You!

Sajeev Answers:

Ludacris once said, “Cadillac grills. Cadillac mills. Check out the oil on my Cadillac spills.” And I feel he described America’s love-hate relationship with Aluminum Eldorados quite well.

Just to clarify, the aluminum Eldorado motors are from the HT-4100 family and the Northstar family. Both motors have aluminum engine blocks with iron sleeves: the place where pistons live. They are all nightmares to fix for various reasons, but some are worse than others. I researched the forums regarding the legendary crappiness of the Northstar Cadillac engine, coming to a conclusion. Which might be so harsh that I’m proactively begging for the Best and Brightest’s mercy.

Here goes: if you have a Northstar-powered Cadillac older than the 2002 model year, it will (more often than not) have cylinder heads that will not seal, needing threaded inserts to fix stripped threads. (These threads are where the head bolts go into the block, so that’s pretty labor intensive.) It shall be expensive and difficult to repair, and there’s no guarantee it’s a permanent fix. Unless you believe in the magic potion known as “Heal A Seal.”

SQ, since you are a young lady, buy a car you don’t like, get over it, and buy an Eldorado later. You know, when you have the time and space for a second car. And then make it a 1979 or 1980 Biarritz with that awesome stainless steel roof and a distinct lack of aluminum under the hood.

Send your queries to mehta@ttac.com

Sajeev Mehta
Sajeev Mehta

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  • Bunkie Bunkie on Oct 04, 2010

    Another day, another anti-Northstar rant. I can't speak for the earlier engines, but I'm with phewop118. The Northstar does exactly what I expect of it: provide smooth, seamless power and a sense of effortless acceleration in my STS. I, too, love the sound. There's a winding, uphill road that we drive each week. I use the manumatic mode to keep the revs up and the STS just powers up the hill with authority making a great noise all the way. Best of all, the "bad" reputation of the STS meant that I got the car for an absolute steal of a deal. With a full warranty.

  • TheRealQuaid TheRealQuaid on Oct 05, 2010

    So long as the coolants been serviced and the car has been driven hard you should be fine. I bought a 2006 DTS and it has 60k hard miles on it and the N*/4T80E hasn't missed a beat. Like phewop118 the motor makes serene noises when asked to move. If by chance the N* motor does happen to give you CHECK COOLANT messages then head on over to the cadillac forums and look up Northstar Performance. That shop has developed a stud kit to replace the headbolts and its what I'm going to do when I get the my 1996 Eldorado on the road. Don't Timesert if you do to much of a gamble like Sajeev said. Go with Norms inserts or the studkit.

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  • 28-Cars-Later I cannot remember what happens now, but there are whiteblocks in this period which develop a "tick" like sound which indicates they are toast (maybe head gasket?). Ten or so years ago I looked at an '03 or '04 S60 (I forget why) and I brought my Volvo indy along to tell me if it was worth my time - it ticked and that's when I learned this. This XC90 is probably worth about $300 as it sits, not kidding, and it will cost you conservatively $2500 for an engine swap (all the ones I see on car-part.com have north of 130K miles starting at $1,100 and that's not including freight to a shop, shop labor, other internals to do such as timing belt while engine out etc).
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