CA18DET Oil Pressure Problems?

[nismo592]

I have a CA18DET sawpped into my 240SX. I don't have a service manual for the CA and I was wondering what factory oil pressure should be at cold and warm up?

The reason I'm asking this is because at cold and warm up it's reading 100+psi. I only now know this because I didn't had an oil pressure gauge before and the one I have now stops at 100psi.

I'm now begining to think that's why blew my stock turbo then my GT25 even though I had it with a restrictor, and now I have a S15 GT28 with Earls stainless steel lines with restrictor and I almost blew it as well.

[mbmbmb23]

What oil are you running? You ever thought your oil passages might be clogged with gunk?

[boost_boy]

I have a CA18DET sawpped into my 240SX. I don't have a service manual for the CA and I was wondering what factory oil pressure should be at cold and warm up?

The reason I'm asking this is because at cold and warm up it's reading 100+psi. I only now know this because I didn't had an oil pressure gauge before and the one I have now stops at 100psi.

I'm now begining to think that's why blew my stock turbo then my GT25 even though I had it with a restrictor, and now I have a S15 GT28 with Earls stainless steel lines with restrictor and I almost blew it as well.

It's normal! All of my cars do it as well. Means you have a good oil pump, but you've been a bad owner because you're revving a cold engine with a crap load of oil pressure and that poor turbo's seal will almost always be the victim. Note to all, let the engine warm-up before revving.

Dee

[sjbsuperman1425]

i dont rev/boost my engine over 2 psi until the coolant is warmed up and the oil temp is above 125..my idle oil psi is around 25-30 and goes up past 75psi at around 3k. its a good little guy lol

[r34 gtr]

Yeah, my rule of thumb is my oil temp has to be at least 140 degrees F before I can wail on it.

I have a GT28R with the stock restrictor (in the 90 degree fitting on the block) and I have never had a problem.

[nismo592]

What oil are you running? You ever thought your oil passages might be clogged with gunk?

I'm running 10w-40 since i'm in a tropical climate.

It's normal! All of my cars do it as well. Means you have a good oil pump, but you've been a bad owner because you're revving a cold engine with a crap load of oil pressure and that poor turbo's seal will almost always be the victim. Note to all, let the engine warm-up before revving.Dee

I always let my car idle for a minute before i drive off, not to mention i also drive slowly in the morning and never go revving as soon as i start to go driving anywhere.

i dont rev/boost my engine over 2 psi until the coolant is warmed up and the oil temp is above 125..my idle oil psi is around 25-30 and goes up past 75psi at around 3k. its a good little guy lol

Thanks for this info, a mechanic here told me that it could be the spring in the valve of the oil pump could be stuck. Saturday we'll know for sure.

[sicj]

isn't the reason for this is the oil pressure sending unit just a switch? it's a on/off switch for the dummy light in the overseas cars...

you can swap a CA20E/CA18E pressure sending unit to get an actual PSI reading for a full sweep gauge

[nismo592]

I circled the spring that I'm talking about. My car is currently at my mechanic and I'm at work presently. I'll soon find out what's the verdict.

[r34 gtr]

Yeah, I suspected that part on my old pump too. Good luck sorting it out. For what its worth, there is a little ball-valve thing in the block behind the oil filter housing. Don't know what it does, but its worth suspecting too.

[nismo592]

UPDATE TO AN OLD THREAD:

Hey guys,
I just wanted to give a long over due update to this old thread regarding my oil pressure issues on my beloved CA18DET , anyway the reason for extreme oil pressure was discover due to a blockage in my oil tank catch set up that I unintentional transferred over during my swap . The "blowby" from the cam cover wasn't going into the catch tank because the intake and exhaust hoses going to it was combined with "Y" adapter that had some kind of filter paper inside and this was completely blocked, hence, causing the block to be pressurized.

Since then I've manage to get a new motor complete with stock turbo step and stock hoses connected to the right places, from TigerJDM in Canada, which is operated by two bosses with who call different prices from each other, not a good thing! Anyway, I've been running my motor stock and so far (knock on wood) no issues.

I've done some minor upgrades so keep it running safely. I've purchased a few "egay" goodies that I can't complain about and most were quite good to my surprise. This includes new 22 pieces engine hose kit (this is not fully installed as yet. I still got 10 more in replace ), radiator hose kit, overflow tank, cx racing SR20 hotpipe with BOV (which I MUST recirculate very soon but I still have to get the parts to do it) and a radiator which is not perfect in finish but it does the job.

This is the CX Racing SR20 Hotpipe, you can say it's an exact fit.


22 piece hose kit , my CA motor comes with a water cooled oil cooler unit so it includes the hoses to replace the stock ones running to it.


This is what it looks like so far, needs to be tidy up and we're good to go. The intercooler is a greddy unit that came with my orginal swap.

[TheMAN]

I think you should be running 0W40 oil instead... better flowability during warm up, and reduced wear... all with the same protections as the 10W40 once the engine is warmed up
the oil pressures won't be so scary high either

[nismo592]

Good that you brought that up, I'm not sure if a 0W is suitable here in the tropics (I could be wrong), I'm actually using AMSOIL Dominator Racing Oil 15W-50. They say it's good for cold starts plus it got zinc and phosphorous which helps to protect metal parts. My oil pressure is about 75 in the morning and goes to 25 to 30 when fully warmed up, exactly as "sjbsuperman1425 " said in his post. Let's just say I'm just a bit more cautious now. One of my near future plans is to add and air to air oil cooler too. Tell me what you think about the AMSOIL.

[TheMAN]

amsoil is a great oil, but expensive... you can do just fine with cheaper brands of oils

anyway, 0W40 is perfect for any climate, you want the oil to be as thin as possible for startup so that all parts gets the oil as quickly as possible... the thicker oils won't flow as well and your parts end up wearing faster instead... it does nobody any good to run 15W50 in any climate! it's too thick! high oil pressures does not mean, better oil flow..... it's quite the contrary in fact!

the only reason why 10W40, 15W50, etc still exists are because there's die hards who still believe in these 30-40 year old viscosity grades because it worked for them back then and don't want to change their ways.... the "thicker is better" mentality
motor oil, like anything, is an evolving technology... you can achieve so much better with the grades that came out not more than 10 years ago... 0W40 is one of them... it hasn't been in the market for too long... it works great! At least with Mobil1's, it's certified for use with many European diesel engines, which signifies its robustness across all temperature ranges

you're doing yourself no good running 15W50... you reduce engine efficiency, which means loss of power and fuel economy.... the oil is harder to pump through, which increases oil temperatures... and as I already said, you're adding unnecessary engine wear during your "cold starts"

frankly, the "I live in a tropical climate, so I must use thicker oil" excuse is nonsense... I used to live in the tropics myself, the temperatures are constantly around 90 degrees only, which isn't anything extraordinary... it gets hotter here in Texas during summer and running Red Line's 5W40 works just fine, and Castrol's 0W30 works just fine in the daily driver... all with long life and no oil degradation (the car using the castrol gets 10000 mile oil changes... 16000km, zero problems)... there's plenty of other car guys who live in arizona, where the heat is even more oppressive... they use either a 30 weight or 40 weight oil, zero problems

you must take what's stated in the manual and throw it out the window... the oil recommendation chart was written in the mid 80s, back when oils were crappy and were prone to break down... that's why every auto maker back then suggested different oil viscosities for different climates... it's not true any more... oil has changed a lot in the past 25 years, let alone past 10 years... you used to have to do 3000 mile oil changes with dino oil, now you can do 5000 mile changes without any worry... so for any car, if you see a crazy oil recommendation chart in the manual, ignore everything but the temperature climate one... then use that as a guideline to choose your MODERN synthetic oil..... so if it was 10W30, choose 0W30... driving the car hard? go with 0W40 or 5W40

no matter the climate, you want the lowest W number you can go
as I already said, amsoil makes great oils, so you can safely switch to their 5W40 oil without any problems... it WON'T break down by any long shot
some of the cheaper brands? maybe... that's why researching what you buy is a must!

[boost_boy]

To each his own in this category and your theory is noted. Though it's not the world according to "Dee", I do run 20w-50 in my turbocharged cars and never have any problems with wear or sludge or whatever. I'm from the very old school, but I do have a gang of $$s thrown into my engines and since I'm the builder as well, I'll stick with what I've learned thorugh my own experiences that has worked for me. The key here is clean oil. Most conventional oils will suffice as long as you mind their service limits in your engine/application. I run a part synthetic and depending on how bad I abuse that engine, the oil is never in there past 2000 miles. A waste, maybe so, but I happen to have created my own theory over the course of my years at wrenching and have concluded that if your mechanical parts are going to fail, regardless of what you do, they will. The oil is just a buffer and as long as it is not contaminated or have a lot of detergents in them, your wear will be limited at best. I did just rebuild my VQ35DE in my Maxima and with only 2000 miles on that motor, I'm still using a 10w-40 conventional oil until I change it tomorrow. Even though that rebuild was very expensive and time consuming, I trust in my theory and will continue to do what works for me as I suggest most of you do what works for you. As for theories, we all have them and it's cool that you can at least share your thoughts with your fellow motor-heads.

[TheMAN]

I follow a more scientific approach instead... I do my research based on oil analyses, looking at actual data sheets (specs) of oils, etc
from my research, those thinner oils performed better in the wear category than the thicker oils, and based on user reports on trying different viscosities of oils, the temperature increase was significant at 50 weight or higher, as well as remarkable loss of power and gas mileage.. those people running thinner oils have no problems, except for maybe oil consumption when running 30 weight oils or thinner.... not all oils are the same, there are always cream of the crop in each brand of oil, that's why I said researching is very important... the good oils always have better high temperature/high shear ratings, more additives, and can take a beating for many miles very well

recent Mobil1 discussions on BITOG suggests that changing their oils sooner rather than later contributed to higher wear metals in their UOAs than going for a medium to extended interval, people have theorized that it may have something to do with the new oils needing to be "run in" first... interesting stuff, but I haven't kept up with it... food for thought!

as I said, oils have come a long way in the past 25 years.... what everyone thought they knew even 10 years ago doesn't really apply today... it's ever evolving just like engines and electronics are... the demand for higher performance, better emissions, and better fuel economy has driven oil companies to research better motor oils... the new API SN rating has significant limits on oil flash points/volatility, high temperature/high shear improvements, better oxidation and sludge control... they also bring back some anti-wear additive goodness, and they now require some amounts of seal controllers (previously found in high mileage oils mostly) in the oil to help keep gaskets lasting longer as average car ownership years increases... dino SN oils today would probably have been considered "synthetic" in the 80s, based on how highly refined and robust they are.... imagine how much better today's SN synthetic oils are compared to the SF and SG oils of the 80s and 90s!

I refuse to get left behind using strictly only knowledge I learned from years ago... things change with the times, so I keep up with the times, just like how doctors are forced to learn new techniques to treat people, mechanics forced to learn new techniques to fix new electronics laden cars, engineers forced to learn new building techniques, etc

[float_6969]

I'm with TheMAN on this. I'm running Mobil 1 0w-40 in the CA. I once heard it put that, "ALL oils are too thick on start up". We don't have the technology right now to get an oil to flow properly at cold temperatures and still be thick enough when heated up. Running thicker oils may increase pressure, but oil pressure isn't what lubricates. It's oil flow. What we all really need are oil flow gauges. But that would be really hard to do, so we used pressure gagues to give us an idea if we have proper flow.

[Izento]

I think I am running 10w30 or something, I can't remember, and my oil pressure is at 100 when cold starting (but I trust my gauge as a estimate since it's on the cheaper side). I think now looking at everyone's comments, I'll switch to a 5w40 now.

[boost_boy]

Make no mistake about by my post in the fact that it was not discarding technology and the advances in the petroleum industries, but merely stating excerpts from my personal experiences and knowledge. Because I own a more modern engine in the VQ35DE, I was forced to abandon that "1 viscosity for all" mentality that I have enjoyed for so long. I also have a camry with a 2AZFE 2.4L engine that I rebuilt about fifty thousand miles ago and guess what oil I've been putting in that thing "20W-50" because of the mentality that I was accustomed to, but guess what, it's perfectly healthy and still is as clean as can be internally. The first owner used synthetic oil (I forget which viscosity) and that things had deep rod knock and had sludged itself to death. Since he told me about that before I bought the car, I had no idea of what was in that engine until I opened it up. It was just disgusting and the #4 rod bearing welded itself to the crank's journal. Got another crank, polished it, new bearings, pistons, rings, rehoned bores, blah, blah and 50k later, engine is still happy.

Have another friend with a 1999 nissan maxima and he also always uses that 20w-50 stuff and 250 something thousand miles on his car, it seems to work. We just change the oil at earlier intervals, but that VQ35DE seem to be the one that needs the more modern oils. To me, it's a sissy engine, but I have to respect what it request/demands and am cool with that. As for the science of today's oils, I'm not in your league "TheMAN" as I pretty much stick to what works my applications. There are too many options of oils to chose from and most of the synthetics are not cheap and also are not a guarantee that the engine will not fail as did the camry engine I spoke of. Mechanical parts will fail regardless and whenever they feel like it and that's a fact. There's been too many mobil1 users and the likes with horror stories of mechanical failure, but I don't see too many people blaming the builder. The oil subject is too sensitive and I tend to stay out of debates of oils because I use what works for me and suggest others do the same. I'm my own builder and tuner, so if something screws-up, I'll make note and just fix it as I the ability and resources to build CAs instantaneously. Good luck with the oil stuff guys

P.S. as for oil flow and pressures, I gauge most of that actions by the amount of oil flowing through my camshafts. If your engine is ticking too much, you have cause for concern. If your engine is flying gobs of oil across your camshafts and your pressure readings on your gauge is reading within normals specs, you're good to go. And that's only IMHO

[TheMAN]

As I said, each brand only has a one or a few "cream of the crop" oils... I completely understand and agree with your sentiments regarding Mobil1... I felt the same way until I started doing some research on different oils... expensive and cheap
What I found out was, Mobil1's High Mileage version was pretty good, compared to their Extended Performance nonsense.... their Turbo Diesel Truck and their 0W40 is also excellent
but personally, I use Shell Rotella T6 as the top up oil for my car... the Red Line 5W40 is too expensive to keep using to top off, so I use that only for the initial fill during oil changes... both are great oils, and the Rotella is some good stuff for 20 bucks a gallon! As good as more expensive oils and better than some expensive oils. It's cheaper and better than any Mobil1 too!

for the daily driver, Castrol Syntec 0W30 works great... commonly referred to as "German Castrol" because it's the only imported Castrol here, and it's highly regarded because it's PAO based, and very stout... beats Mobil1 if you want a 30 weight oil... cheap to get during sales

bottom line is, there's good cheap oils to get that beats expensive boutique brands... the Rotella T6 hasn't been around long, and had I knew about how good that oil was before I bought a 5 gallon pail of the Red Line, I would be using that now solely. It's all in the research... finding out which brand has a particularly outstanding oil It's called being a smart consumer and not being brand loyal Hell, Pennzoil "yellow bottle" used to be pretty unremarkable and highly dissed... but now their SN formulation is awesome... it's LOADED with moly and boron... makes a great break in oil!


btw, early 2000s Toyota engines were known to sludge pretty badly... poor PCV design, small sumps, over optimistic oil change interval recommendations, combined with higher engine temperatures and lack of a manufacturer engine oil standard contributed to this... many people put in cheap SJ oils in there that couldn't stand up to the task... the oils broke down and sludged the motor up! Only high quality oils that had good HTHS ratings and good additives back then could handle this abuse... typically oils that are approved by European auto makers, or have an ACEA rating of A3/B3 (now B4) at least It's now different because SL/SM/SN oils are made to handle these higher stresses as all modern engines run hotter with tighter tolerances...
anyway, give Mobil1 0W40 or German Castrol a go... you'll be surprised how good those oils are, and getting improved gas mileage won't hurt to try to save some gas so you can save some money right?

[nismo592]

I see this has turn into quite in interesting topic regarding oils, I fully understand where "The Man" is coming from and his suggestion is well noted, I'll take this into consideration on my next oil change. Now I just need to find someone here in my country that sell 0W oils...easier said than done
If I ask every mechanic here they will each recommend a different oil and bash each other about why their choice is better. Like "The Man" said, research is important and information share among "true" enthusiast is vital, so I appreciate all recommendations and feedback. Thanks guys.

[TheMAN]

Amsoil doesn't sell a 0W40 oil, Red Line does.... but Red Line's isn't really worth it.... Mobil1's is very good and quite cheap
if you want to stick to Amsoil, just use their 5W40.... it'll be fine... Red Line's 5W40 is slightly better though