newish 4.6 oil pressure issues
Have had a few issues with the way my relatively new 4.6 is running in my D90. My D90 is a '97 and therefore a GEMS engine. I bought my new 4.6 short block engine from CarCannibal/RoverCannibal in Oklahoma City in Dec. of 2010. The engine replacement was performed by a Land Rover certified mechanic. I reused my timing cover from my original 4.0 and had a oil pump rebuild kit fitted from AB installed, as well as a new timing chain, new coolant hoses, have had the radiator recored to 4 or 5 rows. I redid the heads at the time as well. New coolant pump/viscous fan clutch of course.
Since the engine replacement I have had issues with the oil pressure, usually on very cold starts the oil pressure light will not extinguish for 30 sec to sometime roughly 1 or 2 min. I stick to higher viscosity oils (synthetic after break in period) 10-40, 15-50 etc. changing the oil regularly. The truck is a daily driver for me and I have had no issues so far, I drive the truck from Denton to Dallas, TX and back every weekend (39 miles one way) on the highway without issues. Sunday I removed the oil pan and removed/inspected the oil pickup tube to find nothing worrisome.
I took the truck to North Texas British (my local Rover shop) this weekend to have them check the oil pressure; they noted that the oil light did take more time to extinguish on first start than usual but that once it did extinguish the oil pressure was around 40 psi at idle. They insisted on changing out the oil filter to a Land Rover genuine filter to eliminate the filter as a probable cause of the issue. I usually change my own oil and replace the filter with the Mahle filter that AB sells and recommends as compatible with my truck. Once NTB replaced the filter with the genuine version they noted that the oil light seemed to extinguish in a much more appropriate time (1-2 seconds).
At one point NTB recommended adding an additive like Lucas Oil to help the viscosity of my oil, now I'm sorry but shouldn't a Rover V8 with only 40,000 miles be able to run flawlessly without any extra additives?
They also wanted to keep my truck another day in order to let the engine cool off again completely and test it again, however I did not have the time to leave my truck another day.
After their changing the oil filter to a genuine version they reported that the oil light seemed to be extinguishing quicker (1-2 sec) and that pressure at a cold start at idle was 40 psi, and a bill of over $150, I decided it was time for me to retrieve my truck.
The next day, and the day after, starting my truck in my driveway and in fairly warmer weather, the oil light stayed on for at least 30 seconds. The weather here in Texas has been recently warmer (70 degrees) yet the warning light has been staying on as if it were 30 degrees outside.
I am not trying to bash North Texas British here, I am just wondering what I should do with my 4.6 V8 that only has around 40,000 miles on it and a possible oil pressure issue.
I've done some research on Rover V8s and am especially concerned that I may have gotten one of the later factory Rover 4.6 engines with the tooling issues that can cause premature oil pump failure.
I do not want to, nor do I have time for removing my front timing cover to inspect the gears for fractures, etc. nor does that seem like a step I should already be taking.
On the other hand I have also had an issue with my D90 idling unusually high when cold/hot/etc/. I regularly clean the throttle body and the MAF. Perhaps the stepper motor is the issue but I have not scanned any codes that would indicate that. I'm attaching a video of the issue to this thread. The CEL on in the video is due to a P1317 that I have not gotten around to yet with regards to figuring out which sensor is causing that code.
Let me know if ya'll have any suggestions.