Logo
FULL SITE MENU

Bad gauge or bad news on Crusader 454?

N

nightstalker

Regular Contributor
Went for a run today and noticed that the oil pressure gauge at the helm on my starboard engine showed 40 at 3200 RPMs but dropped to 25 when I opened her up to 4500 RPMs for a few minutes. Read normal when I brought the RPMs down and back at the dock at idle. I checked the oil level and found that it was a little less than a half of a quart low. Temperature read 170 when I put the boots to her. Port engines oil pressure read about 40 and temperature was 160 constantly. Any ideas? 1990 454 Crusaders FWC. I'll check the level of antifreeze in the heat exchanger the next time I go aboard. Does anyone know what the capacity of the heat exchangers antifreeze is on these engines?
Nightstalker​
 
Last edited:
I just had the opposite problem a couple of weeks ago, pressure was reading 75 at higher RPM's. I replaced the oil pressure sending unit and now it's around 55 at the same RPM's. The other engine is around 45 at the same speed.

You can replace the sending unit with a gauge and see if you're actually running at 25. I didn't do that, for $28 I wanted to replace both senders anyway.

I would do either first or swap senders from each engine and see if the problem moves.

Bob
 
Just a wild guess here. The symptom points to a bit of oil starving at high rpm. You measure just a 1/2 quart low, but maybe its a bit lower than that. At high rpm, there is quite a bit of oil draining down from the heads and block. Some rebuilders paint the inside of the block to aid in oil drainback. I'm not saying that's necessary to do, but just maybe the pump doesn't have quite enough oil to work with at 4500 with your engine angle, etc. I agree that a second guage be used before we get too carried away. Also, how old is the oil filter, and is it a full size type?
 
The closed cooling system capacity is just over eight gallons.

Concur with the mechanical gauge check.

To continue DD's thought, I've seen some non-ideally maintained engines that accumulated a lot of crud in the rear oil drain holes in the heads, likely due to poor quality oil and infrequent changes. If the mechanical gauge verifies the dash, I'd be inclined to inspect the oil drain holes.
 
Well Mark,

Without mentioning it....that is what had happened to my port engine in that it took some oil filter changes and about 2 seasons of use to get the oil pressure up once it warmed. Were seeing 10 psi on runs so we always dropped the rpm down and over last season and this season with 7 or 8 filters, it is back to normal. I always felt that was the issue with the engine and I am glad it has proven to be the case.

So Nightstalker....these may be very well targeted suggestions
 
In the old days, they used to use kerosene or diesel oil as a 'flushing agent'; a better way in this era is put in full synthetic oil and run a few hundred gallons of fuel thru the engine with frequent filter changes.

I can state that every engine I own that operates with full synthetic oil in it has never experienced any crud build up.
 
my 535i; never a synthetic in 350,000 miles. US govnt killed it August '09. Ran fine. Oil pan inspection 6 mo. before showed no grit or deposits, except for a hard , thin varnish coat on everything.
 
Cash for Clunkers. Taxpayers paid me $4700 for a 24 1/2 year old 6 cylinder car. I still feel guilty; well, somewhat guilty. The Feds paid a contractor to pour some awful stuff in the crank, while the engine was on.
 
Not a fan of aditives but I've used Auto-RX with great success cleaning some sludged up engines. It's a longer term solution though, 1,500 miles in a car so I don't know how you could make it work on a boat engine.

Great stuff
 
Back
Top