Overheating 351W-Help!

Never had a Windsor, had a 4 bolt Cleveland at one time... I'm no expert, just trying to give you a few things to look through until someone more experienced comes along...

It looks to me like you have done quite a bit. As I see it, there are

No coolant flow. Squeeze the radiator hose a bit to feel if the coolant is gushing through, or run it with the cap off and take a look after the thermostat opens.

Timing too advanced. Timing light?

Running too lean. Check the plugs to see what they look like. I would think with the new O2 sensor you might get a code on this, although '90 is early.

Head gasket blown. Don't know about the check you mentioned, you can run either a pressure check on the radiator or look to see if there is any exhaust vanishing away. I suspect your check works along this way.

All of those, except the coolant flow, would give you some drivability hints.

HTH,

Jeff

Your problem sounds like a classic case of a blown head gasket. Since you replaced the plugs, etc before this problem, I have to ask if you are sure you replaced the plug wires according to the 351W firing order or the 5.0L firing order. I have seen this pop a head gasket because one of the swapped cylinders is advanced way too much resulting in severe detonation in that cylinder. IIRC, it is #6 that takes the beating. You can also get a test strip from NAPA to check for exhaust gases in the cooling system. A compression check may also be used to locate a blowout if you are getting combustion gases in the cooling system.

Lugnut

I checked the wires by pulling one off the cap at a time, and each caused the engine to slow down and then when replaced to speed up.

And I used that NAPA kit which uses a blue liquid in a suction unit that is pushed into the radiator opening and uses a suction bulb to pull air out of the radiator. If exhaust gases are in the water, the blue liquid turns yellow. This didn't happen, so I assume there is no head gasket leak.

Could it possibly be a spark advance problem? Or some other sensor?

I don't recall if your 1990 was EFI or carb. Either way, if you check or set the timing, you must pull the SPOUT connector in the harness. This puts the ignition into base timing mode. If you did not pull the SPOUT connector, the timing is likely retarded which will cause if to tend toward overheating. The ECM will also make fuel adjustments to cope with the late timing to further aggravate the problem. You must also make sure the SPOUT connector is replaced after checking or setting the timing or it will remain at the base timing setting at all times - always retarded. With the low mileage on your van, there should have been no need to set the timing since the only thing to mechanically change it without moving the distributor is timing chain wear which is typically negligable under 100K miles on those.

Thanks, guys.

It is EFI. I did not do anything to affect the timing, only replaced the cap & rotor & wires/plugs,

I will check the timing by removing the "Spout" jumper and see if it's at

Thanks for the replies, guys.

It is an EFI distributor. I didn't do anything to the timing.

I will pull off the SPOUT connector and see if the timing is set at the spec of 10 deg. BTDC, just in case.

One thing to mention-at first this overheating was a sometimes thing. In fact, one day I started off to work and after about 3 miles the gauge went way up, so I turned around to go back home and get a different vehicle, but after about a half mile, the gauge went back to normal, and I then went all the way to work and back with no problem.

Tom

How is that possible? I'm not familiar with this, but every distributor I've seen, the timing sensor had nothing to do with the cap or rotor? Is part of the timing sensor on the rotor? Just curious.

Jeff

It is a head gasket leak. I ran it around for 20 minutes, until it got almost to the end of the temp gauge, then stopped and waited until I could safely open the radiator cap.

Then I retested with that NAPA kit with the blue liquid. It turned yellow, indicating exhaust gases in the coolant.

My thanks to all of you for your help in this.

Tom

Jeff, What he is saying is that each cap mold varies some, in the exact positioning of the locating notch and even in the positioning of the towers. A degree or two, very possible on an offshore part, will affect the timing twice that amount at the timing mark indicator. Tom

Thanks for the feedback. I don't envy you pulling heads in a van. You should leave it parked until you do the repairs. Keep in mind that a head gasket blown into the cooling system can allow coolant into the cylinder. This can cause a hydraulic lock of the cylinder than can result in piston breakage, connecting rod or crank bending when you try to start it. You may be able to find the bad cylinder by looking for the clean or rusted spark plug. It is also possible to repair only the damaged head but, I would not do that if you intend to keep the vehicle. It is not a great deal more work to do 2 than 1. BTW, a crack in a cylinder head can cause the same problems as a head gasket. You should have an auto machine shop clean up the heads and check them for cracks. Sometimes a crack is not visible but, will open up when hot. Magnaflux is the only way to be sure. You may take a shot at avoiding this if you can positively ID a blowout area in a gasket. If you can't do that, get the head checked by a good shop.

Good luck Lugnut

Lugnut, Thanks for the reply. I will do both heads, after Magnafluxing and having flatness checked. I appreciate your help. Thanks again. Tom

I doubt that the cap or rotor would be off by more than a degree or two each, even on offshore parts.

But it only takes a few minutes to pull off the SPOUT connector and connect a timing light, to be sure it's all OK. Tom

Moving he distributor housing moves the (in this specific case) hall effect sensor which is attached to the distributor housing.

None of which has anything to do with moving the distributor -housing- which has the hall effect sensor attached to it.

There are no computer controlled components inside the distributor housing on the vehicle in question. Everything inside the distributor related to the computer is an input

-to- the computer, not a controlled device.

Frankly, I am astonished to be reading this from you...

is the pickup in the distributor controlled by the computer?? yes and moving the distributor housing moves the distributor cap, changing the timing. it does not move the rotor. so if you put a distributor cap on that has the contacts that are not in the same exact place as the old one, the timing changes.

so what i said was in fact 100% true.

most people have no idea what you are talking about when you say "the hall effect sensor was just moved"

not everyone needs things to be put in engineer speak to figure out what you are saying.

as a very smart old timer once told me, if you keep your explanation simple, no one will look at you like you are talking out your ass, because they will understand you.

There are 2 Toms involved here- I'm the Tom with the leak The other Tom is giving the advice.

I said that the cap and/or rotor could be off a degree or 2 especially on offshore parts. Turning the distributor does change its relationship since the Hall Effect sensor is fixed to the distributor body, and the ring that activates it ts on the distributor shaft, which is geared to the camshaft. With the engine stopped, then rotating the distributor, it will change the timing. Or if the cap is not exactly right, it will change the timing too, with respect to the distributor body.

Pulling out the SPOUT jumper and connecting up a timing light will assure me that everything is still in time.

There never should have been any need to move the distributor housing unless with the SPOUT jumper removed, the timing is out of spec.

Tom the guy with the overheating.

It most certainly -is not-!

Moving the distributor housing moves the pick-up (be it magneto resistive, hall effect or breaker points). Ignition timing is based upon the specific point where the primary ignition current is interrupted. The distributor cap and rotor have nothing to do with the primary side of the ignition system.

The rotor has nothing to do with ignition timing. The rotor and cap only serve to direct to which specific cylinder the high voltage from the ignition coil is sent to.

Nope. the firing voltage -may- change but the timing is unchanged.

Sorry, not even close.

Be that as it may, it doesn't alter the facts.

Maybe so, but it helps if one has a basic understanding of the differences and functions of the primary side of the ignition system and the secondary side of the ignition system. FWIW, "hall effect" is not "engineer speak," It is taught in any first level driveability class and the device itself was invented over 100 years ago.

Well, that's all nice and home spun but you're still way off track.

BTW, did that very smart old timer ever mention anything about how they used to set the ignition timing by connecting a test light across the breaker points? Did he ever mention anything related to how changing breaker point gap would change ignition timing?

Have you ever changed the octane rod in a EEC-IV TFI distributor, if so, what changed when you did it?