Mazda 13b turbo - weird oil temp related engine noise???

[Reggie]

My car runs a S5 turbo motor, and has a very strange engine noise that appears to be related to oil temperature (ie viscosity or how thick it is).

When the engine is cold, there is a noticeable whirring sound (sounds like a worn out diff), that goes up and down with engine revs. It can't be the driveline, cause it doesn't matter what gear, going or stopped, it's from the engine somewhere.

The hotter the oil gets, the quieter the noise becomes, so much so that after a good thrash you can't hear the noise. The motor runs really well, but it's just this weird noise. I changed the oil from Penrite HPr 40 to a lighter weight oil, and that has improved things... So the noise appears to be related to oil thickness (ie the thicker it is, the louder the noise).

Anyone have any idea what's going on???:confused:

Thanks!!

[madza7]

i run hpr40 and mine does hte exact same thing when cold, but i LOVE that sound :D

i always thought it was coming from the turbo :confused:

[Reggie]

Hey,

Thanks for the info. My previous rotor had a S4 motor, but was running the exact same hi-flow S5 turbocharger, and had no such noise when running HPR40, so there is something different between the two motors....I just can't figure out what it is!!!:mad:

[Simon-AE86]

have you checked things like fan and AC belts? when they are cold they tend to make strange whirring noises then when they are warm... also what about the Altenator bearings>?

Ive never had any noises from mine related to oil thickness and ive used quite a variety of thicvknesses! so its gotta be something else i rekon

[Reggie]

Thanks for your thoughts!!

I replaced perfectly good alternator bearings already, wasn't it. Took the fan belt off, and noise still there.

I was speaking with Simply Maz in Sydney today, and they said it could be the oil cooler hoses being too restrictive. I've just had new hoses made for fitting the cooler, and there are too many bends!!!

You can feel the hoses pulse in time with the noise, so I'm betting that's what it is!!

[Simon-AE86]

thats very weird,... i havent heard anything like that before? but yes i can see it being a problem that will go away once it warms up (oil getting thinner when warmer)

[Razor]

Very strange I havent heard this noise before and I use HPR30 oil tho my oil cooler lines are genuine items.

Have you hooked an oil pressure and temp gauges up to see whats happening there?

Keep us imformed anyways :cool:

[Reggie]

Yeah,

You wouldn't have the problem with the factory hoses, as they are designed properly. The guy who made up the hoses on my car couldn't get the correct angles and so joined together 2 90 degree elbows (not even bends!!), so the poor oil has to go through 2 restrictive elbows doing a 180 turn whilst at it. Getting a proper banjo bolt end made up which will get rid of the problem.

Got me thinking about oils though. I've been a die hard Penrite fan until now, but this Castrol Magnatec 10W/40 is great stuff. My brother was talking to a Castrol technical rep, who was saying it's exceptional. It's API rated as better than the Penrite oil, as is supposed to be a new generation of technology.

My mechanic uses Magnatec in his 12a PP race car, and swears by it. Interesting stuff!!

[Razor]

Maybe other ppl have had good experiances with magnetic but I used it in my 323 when if first came out.. I found a loss of power and responce in the motor so it came out after a week and back went the HPR30.