k722070

hmm, interesting comments, I should pay attention to this one.
I have the same experience as mike, cold start=gurgle noise
after the initial start and drive to store or whatever, on restart no gurgle noises.

Garth S

Could be my ears .... or my car .... but I've only heard 'gurgling' once the thermostat opened - and oil was flowing to the front cooler/fan.

When starting on a cold engine, watch the temp gauge for the first 10-15kms: it rises slightly above the normal level of a line widths below the "1st quarter" mark .... then drops quickly as the T-stat opens and admits a reservoir full of cooler oil + cold oil from the lines and front cooler.
Then, as the remainder of the oil volume equilibrates with the engine core temperature, the oil temp needle returns to a lines width of the "quarter" mark .... for normal driving.

I should add that it takes a fair bit of brisk driving on a warm day before I ever hear the infamous 'gurgle' ... and that is only audible when slowing down and at lower revs ...

Quadcammer

I run the vtwin oil.

I never hear a gurgle, my car runs so cool the thermostat doesn't open in cold weather. I never see above 190 degrees.

NP993

This is what's concerning to me -- since the oil change, the temps where I am have been in the high 20's to the mid 30's. The kind of ambient temps where the motor shouldn't even be running hot enough to open up the thermostat. But now the engine is running hotter (just a little, nothing dangerous), and the thermostat isn't opening. Puzzling.

mongrelcat

I've driven my car many times in the 20's and 30's and the thermostat opens everytime. (Edit: M1 15w-50 & Motul 300V 15w-50)

IXLR8

You might want to feel the oil lines to be absolutely sure.

Aircooled Dave

I get the oil gurgling right at startup, but this seems totally normal.
In looking at the lubrication (oil) circuit diagram, it seems like it is intended to work this way.

1) it is a dry sump so oil is stored in the tank, therefore there is more oil in the tank at startup.
2) The oil flows down to the pressure pump and is pumped through the engine. There is a safety valve and pressure relief valve in this portion of the circuit to dump excess back to the crankcase. There is a second output on the pump that provides oil to the full flow filter/thermostat assy at the tank. If the thermostat is not open due to low temps, doesn't is just dump it back into the tank? When that happens, you get the gurgling sound. It would seem that as temps go up and the varoius thermostats open up, the oil would flow more freely (lower viscocity) and the tank would be holding less of it.

Granted, I could be reading the diagram wrong, but it seems to make sense to me when you consider the amount of oil in the tank at startup, the low temps and various bypasses being used before full flow is allowed to go to the cooler, at which time the tank would be low. Hence the reason you are supposed to check the oil level at full operating temp so there is no oil being 'stored' somewhere in the system and not get counted so to speak.

This doesn't exactly solve the OPs dilemma, but I can't see how an oil change alone would totally alter the behavior of the engine cooling. Perhaps the oil is just too thick and not circulating as it should? 20W-50 seems a bit thick IMO unless you live in a real warm climate. Important to remember here that a thicker oil will provide better pressures, but at the expsense of some flow.

mongrelcat

At 40F ambient, cold start (sat overnight.)

M1 15w-50 (before I switched to 300V)

0:00 - cold, stopped




0:00 - started, idling




0:07 minutes - parked, idled ~1 minute




~0:12 or 15 minutes into the drive




~0:16+ - underway, thermostat open




0:20 - parked, idled ~2minutes




1:00 - parked back at home after an hours drive, idled 1 minute

Slow Guy

I'm going to have to listen for this "gurgling" you guys are talking about, I don't recall ever hearing it. Maybe my exhaust is too loud.......

My thermostat opens right at the 3rd mark on the gauge (apx 8:30 position). The drop after that first opening is fairly significant (as you would expect). I can still see when it opens on subsequent times but the drop is less severe (again as I would expect).

I hope you get this resolved. My guess is the t-stat failed and it's just coincidence it failed after the oil change.

vincer77

I have heard the gurgling noise once while I was stopped, idling and had the radio off. It worried me until I realized what it was.

geolab

In a dry-sump, oil when pumped takes air bubbles with it
On start, oil hot from engine with bubbles enter cold oil reservoir from bottom.
cold dense oil is lighter than hot oil
Difference in viscosity between cold and hot oil, attracts bubbles to hot oil.
Bubbles stick together and become pockets, pockets float up to surface and we hear gurgle sound, all in a fraction of a second, bearing in mind that cold oil prevents hot oil from floating.
Pour a quantity of oil in a glass jar, you will see air bubbles at the bottom, that do not rise like champagne bubbles
If air is very humid, we see a light colored foamy bubbly cloud on surface of hot engine oil. Light colored because water lightens oil color.
As for the front radiator, same phenomena is produced when thermostat opens, but the gurgling we hear takes place in the return tube from radiator to oil tank, after the same process happens inside the radiator
I hope I am wrong

NP993

And, of course, now the thermostat is working fine....however, I already ordered the replacement parts and will rebuild it at the next oil change or the next thermostat failure, whichever comes first.