• We should now be fully online following an overnight outage. Apologies for any inconvenience, we do not expect there to be any further issues.

Diaries of the Noob Mechanic: Fuzzydunlop's '85 MR2

Page 8 - Seeking answers? Join the AnandTech community: where nearly half-a-million members share solutions and discuss the latest tech.
Toggle sidebar Toggle sidebar
J

JCH13

Diamond Member
Sep 14, 2010
4,981
66
91
NutBucket said:
That's correct.
Click to expand...

Zargon said:
yup
Click to expand...

What's your source? Why wouldn't you have to turn the heater on to drain the cooling system?

My experience is really only with my Miata, but that always has coolant flowing through the heater core and "heat" in the cabin is added by diverting more air through the core. It's much cheaper/easier/lighter/simpler than using a valve/junction to divert coolant.
 
NutBucket

NutBucket

Lifer
Aug 30, 2000
27,151
635
126
Source is the valve I see attached to the coolant line going into the firewall/heater core and that said valve moves when the temperature setting is changed.

It's really easy to spot on a car with manual climate control.
 
J

JCH13

Diamond Member
Sep 14, 2010
4,981
66
91
NutBucket said:
Source is the valve I see attached to the coolant line going into the firewall/heater core and that said valve moves when the temperature setting is changed.

It's really easy to spot on a car with manual climate control.
Click to expand...

Cool, and weird.






But I guess those two words sum up MR2s pretty well :awe:
 
Pulsar

Pulsar

Diamond Member
Mar 3, 2003
5,224
306
126
JCH13 said:
Where are you getting your facts?

I've never been in a car where there was an oil gauge that wasn't a real pressure gauge. The pressure switches you are referring to merely turn on the idiot light if there is low or no oil pressure. At least in my experience.
Click to expand...

Took me a bit long to respond. I've handled aspects of assembly and machining of Ford engines for about 10 years now. All of these (including the Shelbies) use an oil pressure switch. It's on, or off, with nothing in between.

In fact we used to jack in an extra sensor - an actual pressure sensor, into the head on the shelby to get more exact results, but that died out around the time the '07 was launched.

The on/off switch is less complicated and expensive than a sensor, and I'd be surprised if any high volume manufacturer is still using a true sensor (unless they had some specific reason they were forced to do so).
 
J

JCH13

Diamond Member
Sep 14, 2010
4,981
66
91
Pulsar said:
Took me a bit long to respond. I've handled aspects of assembly and machining of Ford engines for about 10 years now. All of these (including the Shelbies) use an oil pressure switch. It's on, or off, with nothing in between.

In fact we used to jack in an extra sensor - an actual pressure sensor, into the head on the shelby to get more exact results, but that died out around the time the '07 was launched.

The on/off switch is less complicated and expensive than a sensor, and I'd be surprised if any high volume manufacturer is still using a true sensor (unless they had some specific reason they were forced to do so).
Click to expand...

But did that switch go a gauge face or just an "oil pressure" light?
 
S

sontakke

Senior member
Aug 8, 2001
895
11
81
FuzzyDunlop said:
Short update here.

While I had the wheel well empty on the passenger side I decided to drop the oil pan and re-gasket it. I also painted it, which was probably unnecessary but makes me happy when I look at it now. Took me about an hour just to get it clean enough to accept paint.
IMAG0523.jpg
Click to expand...

What exactly am I looking at? That is not the oil pan! Why is that part being gasket-ed?

- Vikas
 
J

JCH13

Diamond Member
Sep 14, 2010
4,981
66
91
jlee said:
I'd like to see the trickery used to run that with an on/off switch. :hmm:
Click to expand...

Exactly.

Many cars/bikes have an oil pressure switch to say "oh crap! no oil!" but i've never seen a switch run a faux gauge.
 
Pulsar

Pulsar

Diamond Member
Mar 3, 2003
5,224
306
126
The windage trays on the cars I've dealt with (primarily Shelby's) are there for several reasons:

1. Reducing the oil-slosh so that the crank counterweights don't hit the oil bath actually saves some HP.

2. Reducing the oil-slosh can reduce foaming and improve the drain-back so that you don't get starvation at prolonged high-rpm.

Hard to say why your vehicle has it without talking to the designers and testers. It's there for a definite reason - we were always trying to remove them but extended durability testing kept putting them right back in ; ).
 
Pulsar

Pulsar

Diamond Member
Mar 3, 2003
5,224
306
126
JCH13 said:
Exactly.

Many cars/bikes have an oil pressure switch to say "oh crap! no oil!" but i've never seen a switch run a faux gauge.
Click to expand...

Yep. Get in a Ford with a V8 engine. Hit the gas. Did the oil gage move?

I can speak for the newer Ford V8's (2001 on). They use a switch. It's the only oil gage on the engine, and it's on/off - it's an idiot indicator and that's it.

Like I said, unless you have an upscale vehicle or there are engineering reasons they had to use them, I'd be surprised if any newer vehicles used pressure sensors.

I'm not speaking about the MR2 - that's 1991 and may use a pressor sensor.
 
jlee

jlee

Lifer
Sep 12, 2001
48,518
223
106
Pulsar said:
Yep. Get in a Ford with a V8 engine. Hit the gas. Did the oil gage move?

I can speak for the newer Ford V8's (2001 on). They use a switch. It's the only oil gage on the engine, and it's on/off - it's an idiot indicator and that's it.

Like I said, unless you have an upscale vehicle or there are engineering reasons they had to use them, I'd be surprised if any newer vehicles used pressure sensors.

I'm not speaking about the MR2 - that's 1991 and may use a pressor sensor.
Click to expand...

The Mk1 MR2's (85-89) had an oil pressure gauge, but Mk2's have an idiot light. :(
 
exdeath

exdeath

Lifer
Jan 29, 2004
13,679
10
81
Just because it's a gauge doesn't mean the needle ever goes anywhere but "low" when the key is off and "middle" when the engine is running. Analog gauge connected to a digital sensor/switch will result in a needle that only occupies two positions, eg: an idiot gauge :D

My Cobra oil pressure gauge is like this. It's a gauge operated by a on/off switch, so despite being a gauge, is still only good for telling you if there is a minimum oil pressure or not. Like most OEM L--H oil gauges, it's just a fancy idiot light, not a real pressure gauge. Every car I have ever been in with a shitty L --/-- H style factory oil gauge is like this.
 
Last edited:
exdeath

exdeath

Lifer
Jan 29, 2004
13,679
10
81
sontakke said:
What exactly am I looking at? That is not the oil pan! Why is that part being gasket-ed?

- Vikas
Click to expand...

Based on the numerous holes, the flange at the perimeter is sandwiched between the block and oil pan, thus requires a gasket or sealer on both sides.
 
Last edited:
jlee

jlee

Lifer
Sep 12, 2001
48,518
223
106
exdeath said:
Just because it's a gauge doesn't mean the needle ever goes anywhere but "low" when the key is off and "middle" when the engine is running. Analog gauge connected to a digital sensor/switch will result in a needle that only occupies two positions, eg: an idiot gauge :D

My Cobra oil pressure gauge is like this. It's a gauge operated by a on/off switch, so despite being a gauge, is still only good for telling you if there is a minimum oil pressure or not. Like most OEM L--H oil gauges, it's just a fancy idiot light, not a real pressure gauge. Every car I have ever been in with a shitty L --/-- H style factory oil gauge is like this.
Click to expand...

fair enough...but I did have an '86 at one time, so I can tell you the gauge did fluctuate. :p
 
You must log in or register to reply here.

TRENDING THREADS

COMPANY
RESOURCES
FOLLOW
Top Bottom