90 5.0L making funny noises...

[sasilverbullet]

1990 Mercury Grand Marquis with the 5.0L engine with EEFI. 175K miles on the original engine. I replaced the timing chain about 1 year ago. Been using Chevron Delo 15w-40 w/3K OCI's and a WIX oil filter for the almost 5 years I've owned it. Engine/trans runs great, no strange noises, etc.

About 4 weeks ago I was in a traffic jam in 105 degree heat, A/C on full of course. I'm watching the temp gauge gradually climb. Never got out of the 'normal' range, but was over at about 2 o'clock position, right near the limit of the range.

All of a sudden the A/C starts blowing hot air - so I cycled A/C on/off, still hot air. So I left the A/C off. After about 10 mins I tried the A/C again, it started blowing cold again.

Then about 5 minutes later (still crawling along) all of a sudden the engine starts making a noise like I threw a belt, or the fan clutch came loose or something wild and crazy. I was kinda freaking out cuz I was in the left lane of a three lane highway with concrete barriers where the emergency lanes should have been! I put on my flashers, turned off the A/C, opened all the windows and started honking my horn like crazy to get folks out of my way. I moved to the far right and made it to a emergency lane that happened to be under the shade of a overpass! (YEAH!)

I turned the engine off and opened the hood expecting to see utter pandemonium - nope, all looks fine. Coolant level ok, oil level ok, nothing leaking, fan belt tight, weird.

I called the towing service, then called a mechanic. I told him what happened and described the noise. It sounded to me like I threw a rod, or a pushrod or somehting.

So I'm sitting there for about 30 mins in the 105 degree heat waiting for the tow, they called and said it would be over 1.5 hrs before they could get to me. I was torqued...

So I thought, what the heck, I'll start the engine and see if I can pinpoint what the problem was. I started it, it ran a little rough for about 3 secs, then smoothed out and was idling without any noise at all. A/C worked fine, temp gauge was right in the middle. All seemed fine, so I drove off slowly, no noise, all is good. So I canceled the tow and headed home.

Next day I replaced the fan clutch cuz the fan just free-wheeled even when very hot.

So I drive the car for about 4 weeks in the heat, in traffic, no problems and the temp gauge sits about the 1/3 mark now with the new fan clutch.

Then yesterday I was in a traffic jam again for about 30 mins, about 25 mins into it I started hearing a 'tick, tick, tick'. Sounded like valve train noise. It never went above a very low 'tick'. Then when the traffic cleared the sound went away and all was okay.

Any ideas what this could be? Oil pressure? Maybe the rod that drives the oil pump worn?

 

[crw]

I doubt this is it, but I had a very similar experience with a Ford truck, 1991, 5.0L engine. When it would get hot the ignition module (mounted on the valve cover) would begin to die.

I died on a very busy section of freeway when it was 100+ degrees outside. Died on other occasions also. In every case, letting the engine cool would let it run normal again.

Finally it died near a Chevy dealer, and I was really stuck... took it in, and they put a GM part in to fix it! After that it worked fine.

 

[TFB1]

My guess is you've fixed the original problem with the fan clutch and now oil pressure is dropping enough when hot to cause a little lifter tick... If it hasn't had a oil change since the original problem I'd try that, but at 175Kmi the engine is no doubt getting a bit worn...

Above said, I have a friend with a 5.0 in a '88 T-Bird that has something like 350K mi, still ran decent... He was driving it 95mi round trip to work every day, till someone T-boned it...

 

[sasilverbullet]

Originally Posted By: TFB1
My guess is you've fixed the original problem with the fan clutch and now oil pressure is dropping enough when hot to cause a little lifter tick... If it hasn't had a oil change since the original problem I'd try that, but at 175Kmi the engine is no doubt getting a bit worn...

Above said, I have a friend with a 5.0 in a '88 T-Bird that has something like 350K mi, still ran decent... He was driving it 95mi round trip to work every day, till someone T-boned it...


I just recently changed from using Chevron Delo 15w-40 to Amsoil XL 5w30.

Could maybe the thinner weight be a problem? Should I switch back to Delo?

 

[Rand]

i doubt its a ""problem"" but its possible the engine might be slightly more noisy esp. when hot on a thinner oil.

 

[TFB1]

Originally Posted By: sasilverbullet


I just recently changed from using Chevron Delo 15w-40 to Amsoil XL 5w30.

Could maybe the thinner weight be a problem? Should I switch back to Delo?


Well the Delo is approx 40% thicker at 100c, could be lower oil pressure when hot is causing lifter tick... Would no doubt be a good idea to install a oil pressure gauge to check pressure, under 10-15psi at idle is a problem...

 

[OVERKILL]

The lopo's tend to wear the front rod bearings a bit more than the rest. They have the same firing order (cylinder, not numerical) as the old SBC.

The HO variants don't have this problem.

What this means is that as they age, the rod bearings on the front cylinders get a bit "loose" and lower oil pressure. This may be causing lifter tick when hot.

The 15w40 was likely thick enough to mask this problem, but I bet if you put an oil pressure gauge on it, like advised above by TFB1, you'll find you are down below 20psi hot at idle. If not, then that isn't the problem and you may just have a sticking lifter.

In any case, get a mechanical oil pressure gauge on it and get us the hot idle pressure. We'll go from there.

 

[sasilverbullet]

Originally Posted By: OVERK1LL
The lopo's tend to wear the front rod bearings a bit more than the rest. They have the same firing order (cylinder, not numerical) as the old SBC.

The HO variants don't have this problem.

What this means is that as they age, the rod bearings on the front cylinders get a bit "loose" and lower oil pressure. This may be causing lifter tick when hot.

The 15w40 was likely thick enough to mask this problem, but I bet if you put an oil pressure gauge on it, like advised above by TFB1, you'll find you are down below 20psi hot at idle. If not, then that isn't the problem and you may just have a sticking lifter.

In any case, get a mechanical oil pressure gauge on it and get us the hot idle pressure. We'll go from there.


I just installed a oil pressure gauge. It stays at a little over 50psi, that seems high. It still has the Amsoil XL 5w30 in it. I'll give you another update after a couple of days in high temps and in traffic.

 

[OVERKILL]

Originally Posted By: sasilverbullet
Originally Posted By: OVERK1LL
The lopo's tend to wear the front rod bearings a bit more than the rest. They have the same firing order (cylinder, not numerical) as the old SBC.

The HO variants don't have this problem.

What this means is that as they age, the rod bearings on the front cylinders get a bit "loose" and lower oil pressure. This may be causing lifter tick when hot.

The 15w40 was likely thick enough to mask this problem, but I bet if you put an oil pressure gauge on it, like advised above by TFB1, you'll find you are down below 20psi hot at idle. If not, then that isn't the problem and you may just have a sticking lifter.

In any case, get a mechanical oil pressure gauge on it and get us the hot idle pressure. We'll go from there.


I just installed a oil pressure gauge. It stays at a little over 50psi, that seems high. It still has the Amsoil XL 5w30 in it. I'll give you another update after a couple of days in high temps and in traffic.


I assume that is "cold" temp? If not, that's actually quite high. Normally they are in the low to mid 30's hot at idle with a 30-weight in them (up to temp).

Please keep me posted.

 

[jjcom]

I'm trying to think of what could make a low tick tick tick noise on that motor. From the sound of the oil pressure, the engine sounds pretty darn tight so I doubt it's losing pressure.

I've heard those engines develop exhaust leaks around the header pipe and make some light tick sounds. I've also seen (or rather heard) a loose plug wire causing a tick. The spark jumping would make a light tick sound.

Being that you were in traffic when it happened, it could be a small exhaust leak echoing off the surrounding cars making it sound louder too. I'd probably try letting the car idle for a long time and see if you can pin point the noise while at home. Could be "nothing".

 

[sasilverbullet]

Morning drive to work, ambient around 78, 25psi at idle, about 35 at cruising speed.

Supposed to get over 100 today and tomorrow, watch for updates...

 

[OVERKILL]

Originally Posted By: sasilverbullet
Morning drive to work, ambient around 78, 25psi at idle, about 35 at cruising speed.

Supposed to get over 100 today and tomorrow, watch for updates...


That's a little lower than I like (25psi). I'd seriously consider going back to a 40-weight and see if the problem goes away. I'm a big fan of 0w40 and 5w40 in these engines.

Obviously it doesn't fix the bearing clearance issue, which is the reason for the lower oil pressure however

 

[sasilverbullet]

Yesterday in 100 degree heat, no major traffic jams, idling for about 2 mins the longest - 24psi at idle, 35psi at speed. Did notice that the needle increased and decreased with engine speed much faster in the heat.

 

[OVERKILL]

Originally Posted By: sasilverbullet
Yesterday in 100 degree heat, no major traffic jams, idling for about 2 mins the longest - 24psi at idle, 35psi at speed. Did notice that the needle increased and decreased with engine speed much faster in the heat.


I'd just switch back to the heavier oil and see if it solves your problem. The pressure isn't low enough to be a major worry at this point. It is lower than I like, and does indicate some wear, but it isn't super low.

 

[sasilverbullet]

I changed the oil today to Rotella 15W-40, let's see how that works.

 

[OVERKILL]

Originally Posted By: sasilverbullet
I changed the oil today to Rotella 15W-40, let's see how that works.


Keep me posted

 

[sasilverbullet]

Okay, took it out in the 98 degree heat today, lot's of sitting in traffic.

At idle heated up is about 5psi more (30psi). I noticed that if I put the car in neutral, that the oil pressure went up to around 50. It seemed to idle fast, but not too fast.

I think that along with the heavier oil, I'm going to put the car in neutral when I'm in extended idle in the heat. Hopefully this will mitigate the lower oil pressure and keep me running for many more years. Besides all this the car runs fantastic.

 

[OVERKILL]

Originally Posted By: sasilverbullet
Okay, took it out in the 98 degree heat today, lot's of sitting in traffic.

At idle heated up is about 5psi more (30psi). I noticed that if I put the car in neutral, that the oil pressure went up to around 50. It seemed to idle fast, but not too fast.

I think that along with the heavier oil, I'm going to put the car in neutral when I'm in extended idle in the heat. Hopefully this will mitigate the lower oil pressure and keep me running for many more years. Besides all this the car runs fantastic.


Is the noise gone?

 

[sasilverbullet]

Originally Posted By: OVERK1LL
Originally Posted By: sasilverbullet
Okay, took it out in the 98 degree heat today, lot's of sitting in traffic.

At idle heated up is about 5psi more (30psi). I noticed that if I put the car in neutral, that the oil pressure went up to around 50. It seemed to idle fast, but not too fast.

I think that along with the heavier oil, I'm going to put the car in neutral when I'm in extended idle in the heat. Hopefully this will mitigate the lower oil pressure and keep me running for many more years. Besides all this the car runs fantastic.


Is the noise gone?


It hasn't happened so far.

(fingers crossed)

 

[SteveSRT8]

Does anyone have the low oil pressure specification for this engine?

As an example we don't worry much about oil pressure any more because it can be very low and still be acceptable. Plus the PCM in our trucks will pull the spark if it goes under 6 psi, thus usually preventing any damages at all.

My guess is that the OP's pressures are well within Ford specs.