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'01 Seville STS
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35 Posts
Discussion Starter #1
Hi,
I've been told by a very experienced N* professional that there may be some possibility of catalytic converter failure due to the open deck design and oil consumption that are hallmarks of the Northstar.

While I trust his opinions, we didn't get to the data backed reasons for this. Does anyone have any real hard proof about this and also, is there any possibility that his statement that Synthetic oyle might be another reason for this. ( no silly oyle wars here, thus the spelling )

My own thoughts, which are total newbie guesses, would lead down the road of:

Zinc and or phosphorus in the mix may deposit on the interior surfaces and render them less effective?

Please let me know what you all think, and also, give reasons for your statements.

The patient is an 01 STS w ~ 124K miles

Best,
MSH
 

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98 DeVille, 97 DeVille d'Elegance
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7,345 Posts
Converters fail for a number of reasons, flooding with raw gas number 1 I bet. Converter failures are not that common in these years and certainly not as common as some vehicles.
My old F350 pukes enough oil to fog for mosquitoes and with 200k plus on it converter is fine. So no I don't believe the design of the N* causes cat failures any sooner than other vehicles.
 

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2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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68,503 Posts
Catalytic converters wear out - normal - and the qualifier of "high mileage" ups the chances. Proof ? Many more converters are replaced at 150,000 than at 50,000. (and, someone who habitually dumps snake oils into his oil and gas stands a MUCH better chance of cat failure than someone who simply runs a Top Tier fuel)

Today's SL, SM, and SN service oils have much lower ZDDP levels than back in 2002 and earlier, so the zinc/phosphorus thing is almost moot. Proof ??? Google "engine oil api service rating chart".

Oil consumption is a hallmark ? My STS runs a 5W-30 synthetic and gets over 6,500 miles to the quart of oil.

More proof throughout this forum and in Seville/Deville.
 

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White Diamond '03 DHS (with DTS floor shift)
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86,790 Posts
Zinc and or phosphorus in the mix may deposit on the interior surfaces and render them less effective?
Correct. Thus the reduction in the amounts of ZDDP in todays oils.
 

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98 eldo/KD54 w/N37,T96,QA1,D55,DS3,U1Z. U3R next
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2,125 Posts
Catalytic converters don't like excessive amounts unburned fuel or coolant in them......that will lead them to failure.
 

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'01 Seville STS
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35 Posts
Discussion Starter #6
Okay, so how about Synthetic versus Dyno somehow? He seemed to focus on the synthetic not being as good as Dyno because it's long term effects on the Cat?
Thanks to all who have weighed in,
Best,
MSH
 
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