Next project vehicle?

[2000StreetRod]

Coolant crossover tube?

Of all of the different engine coolant configurations (Aviator, Mach 1, SVT Cobra, MK VIII) the Aviator seems like the biggest kluge. I purchased the Aviator oil filter adapter shown in the previous post but I'd prefer to avoid duplicating the Aviator cooling system. The Mach 1, Cobra and Aviator crossover tubes are fairly expensive so I'm considering the less expensive MK VIII.

It looks like it has the two ports that connect to the heads and the other two large ports just like the Aviator. It may not have the ECT sensor but I've learned from 87350gta that the Explorer doesn't use that sensor output - only the CHT sensor. 87350gta also pointed out that the Aviator has a top to bottom flow radiator while the Explorer has a cross flow radiator and I intend to use the one in the Explorer. I'm having problems determining what all of the hoses and tubes in the Aviator diagrams are for but I'll need a unique configuration due to the head cooling modification I plan to implement on both heads.

 

[CDW6212R]

Have you decided what you will do with the engine as far as rebuilding or upgrading etc?

I ask because I still have a pair of never used DOHC heads that came from a 2002 Cobra crate engine. I was planning to work towards the Aviator or the engine/trans possibly, but that changed quickly. The heads I have came from a young man who bought the crate engine for his 98 Cobra, and discovered later that it was too much trouble to convert it to the later heads, COP etc. The heads you can buy now from Ford will be rebuilt and don't include any valvetrain, except maybe the springs/keepers etc. I'm not sure what the differences are among the DOHC heads, they have made so many. If these might be a match to what you have or will end up with, I'd be happy to work it out to get you the new heads(they had a few bent exhaust studs, and one broken back end mounting bolt boss). I haven't yet tried to fix those, I figured replacing the few studs would be best, and the valve springs should be too given the age now.

 

[2000StreetRod]

heads

Don, the heads on the 2003 Aviator are the same as used on the 2003 Mach 1 and Cobra. There was an improvement in 2005 that solved the coolant flow problem in the driver side head and increased the number of spark plug threads from 4 to 9. These heads are in pretty good condition so I plan to use them. I'll remove or modify the rear freeze plug and install a port in both heads to improve flow thru cooling after I take them to a head shop for evaluation. I'll ask about bronze valve guides and a valve job.

 

[CDW6212R]

Sounds good Dale, and let us know what some of that work costs where you are. I have a 95 Crown Vic SOHC that has leaked coolant into the oil once, and I wonder what it will cost to have the heads rebuilt(versus selling the car as is).

 

[2000StreetRod]

coolant crossover tube variations

I think I've determined the differences in the coolant crossover tube variations. For the 1993-1998 MK VIII and the 1996-1998 SVT Cobra the mounting brackets are vertical.

There are 6 ports on the Cobra and 5 ports on the MK VIII.

For the Mach 1 and the 1999-2001 SVT Cobra the mounting brackets are horizontal and there are 5 ports.

Since the mounting brackets attach to the intake manifold, and the manifold for the Aviator is different from the Mach 1, I probably should purchase a Mach 1/Cobra crossover tube although an Aviator one may fit. I haven't been able to find a photo of the Aviator crossover tube. The part numbers for it is 2C5Z8548DB. I haven't been able to find the Mach 1 crossover tube part number. The Explorer doesn't support the ECT sensor so if I need another port I can remove the ECT sensor and use its port.

 

[2000StreetRod]

Cooling system flow?

The Aviator oil filter adapter that includes the thermostat housing arrived yesterday. It mounts on the driver side of the block. The water port is identified by the blue arrow and the oil input port from the oil filter by the red arrow.

According to the workshop manual the upper coolant port on the adapter is connected to the coolant crossover tube and the bottom coolant port is connected to the lower radiator hose.

Normally, the water pump pulls radiator coolant from the lower radiator port. That way when the coolant level is low the flow still continues. What confuses me is the shop manual shows the passenger side of the crossover tube being connected to the upper radiator port.

I couldn't find a good photo of an Aviator crossover tube so I marked up a Mach 1 tube. The tube I've drawn is the heater supply port which indicates there is flow thru the crossover tube from the driver side to the passenger side. The heater supply port is shown in the photo below.

I don't understand why there is flow thru the radiator when the thermostat opens. There doesn't seem to be a pressure differential from the water pump in the path. There's a Caution in the manual that states "This engine is equipped with a cold side thermostat" whatever that means.

 

[4pointslow]

cold side thermostat

I think cold side thermostat means the t-stat is on the bottom where the cold coolant comes in from the radiator, rather than the top where the hot coolant comes out going to the radiator. Most designs have it on the hot side coming out of the engine like our 4.0 SOHC's, where you pointed out the T-stat is on the bottom on the Aviator.

 

[4pointslow]

coolant pipe

This may be an aviator engine. Not sure.
Just posting it because it looks like the coolant pipe picture you posted.

 

[2000StreetRod]

Cooling system flow? (continued)

That makes sense John. That's not an Aviator, Mach 1 or a 1999-2001 Cobra engine intake system.

The Aviator shop manual shows a tube connected between the heater return hose and the rear of the block casting for the water pump.

On the Mach 1 the equivalent heater return comes from the rear under the intake manifold.

The Explorer has a heater supply in a location similar to the Aviator. The thermostat is under the upper radiator hose casting on the intake manifold, driver side.

The Explorer heater return is similar to the Mach 1.

I don't know where the heater supply is on the Mach 1. I guess I should get an Aviator crossover tube and maybe an Explorer heater return tube. Hopefully the heater return tube will not interfere with the Kenne Bell intake manifold if I ever add a blower. I could merge the added head coolant ports with the heater return.

I found a diagram of the coolant components in the shop manual.

The small hose with no number is identified in another drawing as the PCV coolant hose? The two stud/bolts (item 11) fasten the crossover tube brackets to the intake manifold aft of the alternator. The alternator bracket sits on top of the stud/bolts. I have the Mach 1 alternator bracket and stud/bolts which looks identical to the one in the drawing but not the same as the one listed for the Aviator in the Ford parts database.

The database shows the part only fits the Aviator with no mention of the Mach 1.

Would an Aviator owner please look at your alternator mounting bracket to see if its curved or flat - a photo would be very helpful.

 

[4pointslow]

engine picture

Looks like that picture I posted may be a (aprox)2004 Navigator engine.

 

[2000StreetRod]

Alternator bracket

This photo shows the Mach 1 alternator bracket (no longer available from Ford) that came with my intake.

The coolant crossover tube mounts under the alternator bracket at the front where the alternator mounts. That is clearly shown in this photo of a Mach 1 crate engine.

Since the alternators are all the same physical configuration the Aviator crossover should mount with no problem on the Mach 1 intake manifold. However, so far I haven't found a used one for sale. A new one (PN 2C5Z8548DB) is available from Tasca for $72 which is cheaper than a used Mach 1 crossover on eBay.

 

[87350gta]

I had issues with the crossover tube and fan clearance. I used the mark viii tube but had to cut off and relocate both hose connections. There are 2 threaded ports just above the heads on both sides. I have an ect on pass side and I took the port from the explorer intake and threaded in into the driver's side port. That feeds coolant to my heater core. Out of the heater core goes to back of water pump fitting. If you are not using the mechanical fan assy, you will have more room. The aviator coolant crossover should give you more room also.

 

[2000StreetRod]

no electric cooling fan

Thanks Luke. I wasn't planning on using an electric cooling fan for the radiator - just the stock Explorer radiator, shroud and mechanical fan.

Do you think the heater coolant return at the rear of the block casting for the water pump is adequate to also accept flow from the rear of the two heads? I've read that it is thin metal and rather flimsy but there is an upgrade available for the nipple and the Mustang tube. Is the only thing that holds the tube to the nipple the O rings?

 

[87350gta]

The tube also bolts to the rear or front of the head, depending on the shape of the tube. Mine is coming out the front like the aviator, and is just floating, but my fitting on the water pump is a barbed fitting with a clamp. Only the newer blocks have the slip on fitting with o-rings. If you can run the tube that goes to the rear, you should be fine hooking it up to the rear outlets. I can't remember how you were running your heater hoses, but coming out of those freeze plugs into the heater core then into that water pump fitting would work nicely. And it would look cleaner in the front.

 

[2000StreetRod]

PCV valve

The Aviator wiring diagram shows the PCV valve being electrically heated and Rock Auto lists the same valve being used on 2002 and later Explorers.

But the 2002 Explorer wiring diagram doesn't show the PCV valve. Also, the Aviator drawings show coolant hoses going to and from the PCV valve but the Rock Auto drawing doesn't show that capability. What PCV valve did you use?

 

[87350gta]

I am using a standard pcv without any heater. I think maybe the electronic heater was only on some v6 explorers, but I would have to do some research to be sure.

 

[2000StreetRod]

Standard PCV valve

I was hoping that's what you would post. I'll do the same thing.

 

[2000StreetRod]

planned coolant flow

Here's my planned coolant flow diagram using the stock Aviator crossover tube and the Explorer heater control valve.

I think I'll purchase the head cooling mod kit that uses hose barb fittings from Modular Mustang Racing because the -AN fittings one interferes with blower intake manifolds.

 

[99SportX]

This looks like a fun project. Subscribed!

 

[2000StreetRod]

missed out on 2002 Explorer

I normally check craigslist several times throughout the day but Sunday I was involved with family things and then my wife and I went to a Christmas concert and to dinner after. When I finally got to the computer there was a black 2002 Explorer listed with RWD, and V8 with "going out oil pump" for $850. I called right away (9 pm) but it was already sold. I really want to find one that is still drivable so I can check out the transmission.