LoneStarMusty

Hey Guys,

I've got a 65 mustang with a 302 from a 1970 mach 1. For i know the engine got fully rebuilt a few years ago.
I had no problems with over heating or oil pressure before. I was cruising around and ran without fuel. Just filled him up with
a jerrycan and drove to a filling station and fully filled up. I start again and drove away when i noticed my oil light goes on.
When i was in N or driving at low revs the light keeps on burning. When i rev'ed it the light goes out and back on again at low revs.
I checked my oil on the spot and it was clean and full. Drove a few blocks home and find that he was running real hot (no temp gauge or oil pressure gauge).
So far i hooked up a oil gauge and get around 50 psi (cold engine).

I did do some searching and reading already and find a lot of guys with the same type of problem.
Before i start replacing random things i would like to find the actual problem.

I thought maybe my oil pump is bad but read this will not result in a engine really overheating.
Then i read about the main barrings but there are no strange noises as far as i can tell.

Also there are people talking about cooling problems (cooling system) which could cause low pressure due to the oil getting thinner.
Than again i read this can't result in very low pressure like i experienced.


What should i do/test first and what do you guys think?

fastbackford351

Sounds like two different problems to me.
I don't have a clever answer as to why you had no problems before you ran it out of gas other than stuff happens.

You say that you have no temperature gauge hooked up. I'd get some ground truth on what "hot" really is and hook one up.

What kind of oil pressure are you reading when it's warmed up and at idle?

rmodel65

+1 you need to find out the real temp and the real pressure..buy one of those triple gauge sets from the parts house and get a reading the gauges in cars are pretty inaccurate...

rbowmar

I agree with the others--reliable gages are required to get accurate measurements. Since oil pressure is proportional to RPM, a working tach can give more consistent readings.

jlg2002

1st thing to do is figure out if you have an oil pressure problem or not. minimum is 20 psi at idle HOT. Use a known good test gauge hooked to the oil sender outlet port. if the oil pressure goes down you have problem that will require oil pan removal.
An it is possible to have oil pressure decrease as a result of the engine temp going way high. you should smell the engine and probably hear a lot of clattering.
Next figure out if its hot - how do you know it's hot without a gauge?

rmodel65

min at idle is really about 10psi the rule is 10psi for every 1krpm the engine is spinning

fastbackford351

10 psi per 1k. Yep.

LoneStarMusty

Thanks for the input so far!

Today i took some time to check a few things.
I don't have a temp gauge yet so i tried to get a reading with a Multimeter on the temp sensor but when i tested the sensor in cold and boiling water the ohms were jumping all over the please so i still need to get a good temp sensor first. I'll get a 3way gauge asap.

I started the engine and let him run for a few minutes (something like 5-10 minutes). Again he begin to run very hot in a few minutes (i know how it is supposed to feel and this was way hotter).
The radiator was really getting (almost smoking) hot so coolent should flow nicely through the engine and the thermostat should work as far as i can tell.
I have a good oil pressure guage attached and cold / hot was about 45 psi. I think the problem starts with overheating and finally this results in low oil pressure.

I checked the spark plugs today, i found that the 2 front ones on each site were black and the 2 rear ones were more like a coffee brown color.

Again, I have enough oil en coolant and both are looking good as far as i can tell.
The engine is not making any strange noises and i'ts not smoking badly.

Anyone got any ideas?

LoneStarMusty

I forgot to tell that i could clearly see a bit of coolant beeing pushed into my resorvoir. This tells me the engine is too hot, the coolant systems holds pressure allright and thermostat should work (otherwise coolant should just stay cold in radiator i guess). My radiator cap says "made in Mexico", could this be the problem?

I also thought about the fan clutch but i haven't got one (fan is directly attached to belt pulley / waterpump).

So this leaves...?

rmodel65

coolant is supposed to go into the res when it gets hot..until you really know if you are overheating no one can really help you. have you bought the mechanical gauges yet?