Cadillac Seville / Cadillac Eldorado Forum Discussion, STS vs SLS in Past Cadillac Vehicle Discussion; So let me start off by saying I am not new to owning an older Cadillac. I had a 1994 ...
- 09-19-13 01:47 AM #1Cadillac Owners Member
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- Sep 2013
STS vs SLS
So let me start off by saying I am not new to owning an older Cadillac. I had a 1994 Red Cadillac Seville SLS and the engine blew a head gasket so I turned around because I loved the car so much and bought a 1995 Black Seville SLS and it currently has 170,000 miles on it and is still purring like a champ, and besides the normal wear and tear, numerous quarts of oil, water pumps, thermostats etc. It has been a great car, but with all cars they are gonna break down at some point so I am preparing myself for my next Seville. So ultimately I am considering buying a 2000-2003 STS or an 2000-2004 SLS. With that being said, I have read numerous forums stating that head gasket failures are common among STS model, but I really can't find anything about the SLS model and head gasket failures. Are they just not as common with the SLS model is there a difference in the way the 4.6 NStar was made? Any help or advise would be greatly appreciated.
- 09-19-13 02:41 AM #2
There's absolutely NO difference in HG failure rate between the two trims levels.
In '00, a switch was made to longer head bolts, greatly reducing failure rate.
In LATE '04, a switch was made to coarse thread bolts, pretty much eliminating it.
A much bigger concern when choosing between the two is the suspension.
Most SLSs have passive suspension - replacement shocks and struts are cheap.
STSs with a build date before 1/15/02 have CVRSS active suspension. Shocks and struts are ~$1,100 each at the dealer, ~$500 each online. Monroe makes active replacements for ~$350 each. You can also convert to passive using resistors... But then there's really no point in buying an STS in the first place.
STSs built on or after 1/15/02 have MagnaRide active suspension. Stock replacement shocks and struts are slightly cheaper than CVRSS replacements, but there is no aftermarket alternative, and you cannot convert to passive.
- 09-19-13 03:10 AM #3
Thanks. Appreciate that! Quick question, would a compression test be the best way to tell of an impending head gasket failure?
- 09-19-13 03:35 AM #4
Re: STS vs SLS
there is NO WAY to predict a head gasket failure -
the BLOCK TEST is the definitive test to verify a failed head gasket -
a compression test is useless -
there is no aftermarket alternative, and you cannot convert to passive.
actually - there is a member who claims to have converted MANY magnarides to passive -
and uses resistors to fool the system -
- 09-19-13 04:06 AM #5
Yes, and every time the question comes up, he says that, but provides no resistor values. So for now...
Strange that none of the companies offering conversion kits offer one for F55 Sevilles, if it's as simple as a different resistor.
- 09-19-13 04:27 AM #6