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91 deville
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Discussion Starter · #1 ·
Hello, looking for some guidance on purchasing a 2010 CTS 3.6 with 150k miles.

My concern is the oil pressure gauge reading. It has the red line, then the next hash mark which the needle sits just beyond that at idle. My guess would be red is 0psi next hash is 12.5psi needle points to ~ 17psi then next hash is 25psi (added picture with blue line where pointer is, it is not where the point is in the picture).

The pressure goes up while driving, at 50psi cruising around but will fall at idle. Is this a hard pass? Or is this normal for said vehicle? Or is this one of those maybe things? Car runs good, no noticeable noise. Thanks for your time.
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08 CTS DI
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Hello, looking for some guidance on purchasing a 2010 CTS 3.6 with 150k miles.
Normal hot idle oil pressure per GM is at least 10 psi. Inquire about the timing chain status, if they have not been changed, add $3k to your purchase expense and take a look under the right rear side of the fuel tank to look for evidence of a possible fuel leak from the elbow coming out of the fuel pump module up top.
 

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91 deville
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Discussion Starter · #3 ·
The owner is not aware of the timing chain but only had the vehicle for 8 months. Did a service history check and nothing noting timing chain related. Thanks for the info and think I will pass. Not looking for a project even if it is 3k off.
 

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2002 F55 STS, 2014 Explorer XLT, F-150s
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Perfectly normal for hot oil pressure to vary from 12 - 15 psi at idle to around 45 - 50 psi on the road. Oil flow quantity varies with engine speed - hot idle, low flow, low pressure. Hot cruise, higher flow, higher pressure. Max pressure is limited by a bypass spring and plunger in the oil pump or filter adapter. Above XX psi that bypasses excess oil directly back to either the oil pan or pump intake tube.

Pressure is pump speed and mechanical (bearing clearance) condition; Flow is lubrication and cooling. Oil is the only medium that cools all the engine reciprocating guts - it runs at 185 - 210 degrees and passes off its heat to the block and pan where that heat is removed by coolant and transferred to radiator airflow.
 

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2011 CTS Coupe FE3, 2003 Thunderbird, Gone 2013 ATS, 02 Deville
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What oil are you using? name brand, model, and weight? like 5W-30.
How many miles are on the oil since the last oil change?
where do you live, ambient temperature?
What is the engine temperature when the engine has been driven for 30 minutes?
What is the oil pressure when the engine is at operating temp, in park, at 2,000 RPM? and then at idle?
 

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The OP doesn't own the car-- he's looking into purchasing it.

Considering the mileage, gauge reading, and short ownership from the seller that car would be a hard pass for me.
 
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Picture is showing 25 psi and is a normal hot idle. OTOH unless a steal are plenty under 100k miles at least in Florida.
Picture is a representation, not an actual shot of the car in question.
 

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2014 ATS 3.6 Premium RWD, 2016 Corvette Z06, 2018 GMC Sierra Denali 2500HD Diesel
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From his description, he thinks it is sitting at about 18 PSI at hot idle which is fine especially since the CTS in gear (at least my 2008) had a somewhat lower than most cars idle speed which is part of the reason for the shaking/vibration felt in some of that generation at idle.

Of course, if you really want to make a decision based upon a fine measurement of oil pressure then I would want to make sure it not only has the correct weight and filter cartridge but more importantly the test is done with a known accurate external gauge instead of relying upon a 12 year old built in sensor that wasn't intended to be high accuracy even when it was new.

There are very few vehicles I would consider keeping at 150K or over and it would be a bigger stretch to buy someone else's unknown maintenance/treatment vehicle unless it was dirt cheap. Particularly a luxury car that has more than the usual number of things that can go wrong. I think the old International Harvester corp had the best name for them in an ad campaign when they called them "necessories" which is a good description of some of many features of these cars which become necessary accessories because you don't really have to have those features except they are so integrated into the overall car interface that if they aren't working then the car may not be usable in a practical sense.

Rodger
 

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91 deville
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Discussion Starter · #13 ·
Thanks for you all response. Still in the market so any info is good. I see a few 2008 for sale, did these get the timing chain fixed or is it more of only if they had issue?
 

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Thanks for you all response. Still in the market so any info is good. I see a few 2008 for sale, did these get the timing chain fixed or is it more of only if they had issue?
There was a special extended coverage for specific '08-'09 models depending on VIN which prolonged coverage for 10yrs/120,000 miles. That campaign has long since reached its conclusion.
 

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2009 CTS 3.6L DI Premium, 2014 CTS VSport
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Thanks for you all response. Still in the market so any info is good. I see a few 2008 for sale, did these get the timing chain fixed or is it more of only if they had issue?
Unless the PO can provide a record of timing chain replacement, you should budget for the repair.
 

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quite fitting for "Old People" country 🤪
I had the same thought. The down side of the low mileage is dinged up exteriors and filthy interior as vision and other senses deteriorate. You pays your money and takes your chances.
 
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Are mostly garaged and rarely "dinged up". You are thinking of F*rds.
No, I'm thinking of the realities of old age. We'll all get there someday, with any luck. Or are already there. Don't take it personally ;)
 
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