Like Tree0Likes

oil temp 502mag


Old 09-13-2007, 03:23 PM
Thread Starter
Join Date: Sep 2007
Location: syracuse newyork
My Boat: 2001 formula 271 fastec
Posts: 4
Default oil temp 502mag

I have a 2001 271 fastec with a 502 mag.When running at 40 mph and above for 20 min or so the oil temp climes to 230 and will go at times as high as 310 which turns on light and warning chime .The pevious owner repoorted this to the selling dealer and they went to formula and they state this is not abnormal for this boat with these gauges .Im not buying that .It has merc marine 25w40 oil .Water temp runs at 170 at idle or wot. oil pressure is spot on .I feel I should run around 210 tops ? water temp of lake is 68 degres .I have cked the oil cooler for blockage and all so flushed it .Will seinthetic help ? p.s. the boat only has 125 hrs. on it
hot n hazy 2 is offline  
Reply With Quote
Old 09-13-2007, 03:42 PM
Charter Member # 55
Charter Member
Griff's Avatar
Join Date: Oct 2000
Location: Omaha
My Boat: .......32............. ............Active Thunder....
Posts: 16,250

310* is too high. You want consistent oil temps at cruise speeds to run over 212* to burn off condensation.

You need to get an infrared reading with a temp gun of the oil temp in the pan.
Griff is offline  
Reply With Quote
Old 09-13-2007, 03:55 PM
Join Date: Jan 2004
Location: Tennessee
Posts: 4,494

I have installed larger oil coolers on several 502 MPI's. The stock cooler is not quite big enough. A 3" cooler will solve your problems. I have had it lower the oil temp over 80 deg. in some boats. Conventional oil is breaking down at that temp. Synthetics don't break down until about 400 deg., so you may want to switch until you can have a bigger cooler installed. Hope this helps, Eddie.
Young Performance is offline  
Reply With Quote
Old 09-14-2007, 12:46 AM
iTrader: (1)
articfriends's Avatar
Join Date: Jun 2004
Location: Frankenmuth
My Boat: EX 99 MPH 272 Baja owner, 1999 Scarab 33 AVS NOW
Posts: 6,172

The stock oil cooler is pretty small,buy a bigger one and never look back. You could also replace your oil relief valves in the block,they may be opening or hung open allowing oil to bypass the cooler and filter,Smitty
Attached Thumbnails oil temp 502mag-oil-lines-004.jpg  

Last edited by articfriends; 09-14-2007 at 12:49 AM.
articfriends is online now  
Reply With Quote
Old 09-14-2007, 09:15 AM
Join Date: Apr 2005
Location: South Bend IN
My Boat: 96 292 REGAL
Posts: 110

artic is very smart on this issue. I had oil temp problems in the past and I bought the big hardin cooler with a thermostat. Without the different bypass valve, it only dropped the oil about 10 degrees. The synthetic mobil dropped it a little more and it was tolerable, but the bypass valve was more important in my book rather than the cooler. I would take a infra red temp other places. There are alot of stock 502's with a stock cooler without issues. Search in the forum and you will find endlass threads on this subject. Good luck. Dan
REBEL4845 is offline  
Reply With Quote
Old 09-14-2007, 11:03 PM
Join Date: Oct 2005
Location: Oshvegas WI
My Boat: Anything on the lot!
Posts: 520

although i have little experience with this issue on 502's, i have spoken with reps. on the mercury technician help line in deatial about this issue on 496 applications. they have told me that oil temps of 250 or greater are commpon and pose no threat to the motor or any related system. - from the horses mouth....
JUKED YOU is offline  
Reply With Quote
Related Topics
Thread Starter
Last Post
General Q & A
09-25-2008 01:59 PM
General Q & A
05-01-2008 01:48 PM
General Q & A
09-11-2006 08:15 PM
General Q & A
05-22-2003 11:06 PM
General Q & A
05-28-2002 10:13 PM

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

Quick Reply: oil temp 502mag

OSO Sponsor
OSO Advertiser
OSO Advertiser
OSO Advertiser