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1970 Ferrari 365 GT Engine Coolant Thermostat Motorad - Standard

P311-2166D11    248-180  New

Motorad Engine Coolant Thermostat
  • Thermostat
  • 180F OEM Recommended Temp
  • Standard
  • Manufactured with OEM quality materials and safety standards by an OE Supplier. Stands up to even the most demanding automotive cooling systems. Manufactured with OEM specifications and processes. Copper case and wax compound assures rapid response to temperature changes in the coolant. Offset design, air relief valve, and OEM style seals included where applicable
Brand: Motorad
Additional Fitment Information:
1970 - Ferrari 365 GT
1970 Ferrari 365 GT Engine Coolant Thermostat Motorad - Standard

P311-2166D11    248-180  New

Motorad Engine Coolant Thermostat
  • Thermostat
  • Temperature 180F OEM Recommended Temp
  • Standard
  • Manufactured with OEM quality materials and safety standards by an OE Supplier. Stands up to even the most demanding automotive cooling systems. Manufactured with OEM specifications and processes. Copper case and wax compound assures rapid response to temperature changes in the coolant. Offset design, air relief valve, and OEM style seals included where applicable
Brand: Motorad
Additional Fitment Information:
1970 - Ferrari 365 GT

Latest Ferrari Repair and Thermostat Installation Advice

CarJunky AutoAdvice

Heater Issue: Dealer Stumped...

Showing 2 out of 20 Posts | Show 18 Hidden Posts
Question From ImaStumped on Heater Issue: Dealer Stumped...

To begin, Engine is at operating temp; no over or under heating issues with engine temp.

1. When at idle, the cabin heat from the vent is luke warm even though the engine is at operating temp.
2. When you accelerate and while you're driving, the air gets hot, but not as hot as I would expect; but much warmer than at idle.
3. As you come to a stop, the air out of the vent begins to cool back to luke warm.
4. Accelerate and it heats up...

>Dealer replaced Thermostat - didn't fix.
> Burped it, confident there is no air in the system.
>There are no service codes.
>Dealer confirmed no issue with water pump.
>Air gate is functioning properly.

One peculiar thing I noticed...The hose leading into the core is hot, but the hose coming out is luke warm.

Any idea what is preventing the full flow of hot water to the core? Antifreeze is clean, low miles, well cared for...as I said the dealer is stumped...3 mechanics came up dry...want to start throwing parts at it...



At the start, poor to no heat from at the cabin vents.

At the end, 140’s to 160’s while driving, 120’s at extended (5 min+) idle with fan on high…at the low fan setting, temps were in the 140’s at idle.


The easy way:

Take it to a reputable shop and have them flush and fill using a vacuum system…$100 to $200

Do it yourself…an hour or so of time and the cost of a gallon of 100% antifreeze (NOT the 50/50 stuff)…$9.00

With a COLD engine...

1. Pull both heater core hoses off near the throttle body.

2. Using a garden hose, reverse flush the heater core, then forward flush.

3. Flush the other two holes that lead into the engine.

4. While the garden hose is connected to the core input hose, reattach the core output hose while the water is pouring out. Water/air will then pour out of the engine hole where the input core hose connects.

5. As fast as you can, remove the garden hose and reattach the core input hose to the engine...the goal is to be fast and avoid air in the line as much as possible.

6. Start the engine, make sure the coolant tank has proper amount of fluid…work any bubbles out by squeezing the hoses..once the coolent level stabilizes, drive the car with the heat on high…you should have good heat with vent temps 160+.

Cold engine again:

7. The flushing diluted your coolant…so you’ll need to get that back to a 50/50 level. The radiator drain valve is impossible to reach…absolutely ridiculous location…With reservoir tank cap removed, I pulled off the reservoir tank radiator hose, held it higher than the cap hole on the tank, then poured pure antifreeze into the hose which flowed into the top of the radiator, pushing the diluted antifreeze from the bottom of the radiator into the reservoir tank.

Use a “floating balls” tester on the antifreeze in the tank…if it’s too weak, empty the reservoir (I used a drill pump) and pour more pure antifreeze into the top of the radiator…repeat until you get the proper mix…it took me about 4 repeats and ½ gallon of pure antifreeze to reach the -25 level for the coolant. The engine coolant is also diluted, so you’ll need to drive and repeat the above procedure until that coolant tank fluid specs out the proper “floating ball” level.

Response From nickwarner Top Rated Answer

All Ferraris do that.

If by chance this isn't a Ferrari, please tell us what the year, make model, engine size, mileage and other such pertinent details are.

Either you have air in the sytsem that is being a royal PITA to remove, or you have a plugged heater core.

Response From ImaStumped

2005 Mazda Tribute, V6, less than 10,000, yes, 10,000 miles..car is like new...driven regularly, but short distances only.

I will add that when it in to the dealer, the air was luke warm all the time...after service, it's does get very warm, not hot, while driving only to cool again at idle. I'm a backyard mechanic and would normally investigate/fix myself, but I opted for the dealer to save time...figured a trained mechanic could whip it out in a hour easy...boy was I wrong.

I strongly suspect air in the core even though the dealer says they did what was necessary to remove any air....I'm going to assume there is still air in the core and I would appreciate any tips to get it all out fast. After I am sure there is no air, and the problem still exists, then I will disconnect the core hoses and reverse flush...but I'd like to do that only as a last resort.

Response From Hammer Time

We use a vacuum fill method. That's about the only way to insure you get the air out. They make a number of different kits for doing that.

Response From Tom Greenleaf

Too bad you are here at all as the problem was put on techs that have messed up somehow. Air or plugged core. It can work I think you said so either still possible.

Where is the suggestion to flush it out and fill it properly if it does need and many do need a vacuum fill or takes too long to play games to get it right.

YOU are risking an overheat but have sought out help sadly it should have been taken care of and you only worry about paying for it,


Response From ImaStumped


I’ll recap:

Prior to the dealer attempt at repair, the car struggled to blow warm air.

After the dealer attempt, it would blow very warm, not hot, air as long as you were not idle…at idle, it was luke warm at best.

It dawned on me, after my repair attempt, that I should be using a thermometer in the vent to get real temps…on to my repair attempt and thermometer results.

I went through the standard (non vacuum) procedures for getting air out…no improvement.

I then removed the core exit house at the point where it branches off to the carb intake. There was no fluid in the hose…nothing but air! Pulled off that hose and I didn’t lose a drop of coolant…something wrong right there.

I then moved over and disconnected the core input hose from the area near the thermostat…fluid poured out.

So now I have four hose that I can flush…I back flushed the core first, then forward flush it…no obstruction, water flowed easily in both directions.

I then turned the hose on the other two holes and water flushed out…no obstructions.

So, I’m very satisfied that it’s not an obstruction.

I put everything back together, worked the bubbles out and was ready to test the heat.

I let the engine warm to operating temp, then went on a 20 minute drive that included 5 minutes at 70mph; here’s the temp results:

Heat and Fan were both on high and system was set to recycle the cabin air.

Outside air temp was ~60 degrees.
165 Degrees was the hottest vent temp recorded.
140’s was the typical temp for 35mph city driving.
130’s was typical when stopped at a light.

Once home, I let it idle in the driveway for 15 minutes.
5 minutes in, the temp had dipped to 107 degrees.
Over the next 5 minutes in bounced up to 116 and stayed there solid for the last 5 minutes.
Engine operating temp was rock steady right in the center of the dial.

Would this be considered normal for a 2005 Mazda Tribute? I tested my other car and hottest temp it hit was 170…so it seems like my max temp is good in the Mazda…but the other car idled at 145…30 degrees more than the Mazda?

So what do you think folks? Is that as good as it gets? The 140 to 160 range was hotter than I’d ever felt it…So I definitely made a big improvement with the flushing..but does that 107 and 116 at idle seem odd?

PS> What temps would you expect?

Response From Hammer Time

Just because water flowed through the core does not mean it isn't restricted. These cores are engineered with a bypass design. You can have 90% of the core blocked solid and still have coolant flow through it in the other 10% but it will not produce heat that way because you are only using a small portion of the core surface..

Response From Tom Greenleaf

HT just said it that the "core" of heat exchange items are not always the best clue. He called it "bypass" and what can and is that these things are like a maze such that one plugged tube takes out a lot of others. In short it isn't necessarily a tube and fin, tank to tank idea so could confuse the diagnosis.

Still not sure it has proper flow or air ducting on this car. Both hoses should be hot to the touch even when heater is working hot water/coolant doesn't lose a wild amount of temp or shouldn't.

You noticed little to no coolant loss unhooking a hose? Some up high in the system you don't. Air always an enemy which vacuum filling solves short of standing vehicle on rear bumper and filling it. No kidding it can help to tilt some mildly fussy cars.

Note: heater is not supposed to burn you out. Most will not blow air close to engine operating temps and those that do (older stuff) are still below engine coolant temps.

You mentioned water pump tested well. My question there is how was that determined? Weaker or corroded impeller fins usually show as working better at higher RPM and would anyway and so would some air in system but would cause alarm that it's inadequate flow for some reason that could be the water pump,


Response From ImaStumped


The car has under 10,000 miles. Reservoir tank is factory clean. Dealer replaced thermostat, it looked brand new. The hoses and connectors from my attempted repair were pristine inside and out. We're really talking about a brand new car here...this is my dads car, so I don't know when the issue began and since he's elderly and drives it so little, he's not sure either..but in the past it worked fine...so somewhere in the recent past did this begin.

"air ducting"...given that it now hits the 160's for highs which is equivalent to two other cars I own, I doubt the ducting is an issue, but I will inspect to rule it out for sure.

"You noticed little to no coolant loss unhooking a hose?" The point at which I made the two disconnects is a foot or more below the reservoir cap. It was the core exit hose that had no fluid in it. When I removed the reservoir cap, the tank level started to drop and then fluid came out the core exit hose...so there was air in that hose prior to my disconnect.

"Note: heater is not supposed to burn you out." Understand, and given that my other cars max at the same temp as the Mazda, I'm satisfied that it is reaching is maximum output. The problem is at idle with it dropping to 116...my other cars hold around 140...maybe this is normal for this car? Seems like all machinery has it's shortcomings..maybe it's just a design flaw?

"You mentioned water pump tested well." The dealer mechanic said that...all I can say is that the engine heats to operating temp and sits there rock solid...no matter what you do, the temp will not push past the center of the dial...so it really appears to be doing it's job.

"Weaker or corroded impeller fins"...well, I refer back this car being basically new...with pristine coolent and it's ability to push 170 like my other cars and hold ~140 like my other cars....the only problem now is at idle with the drop to 116...again, normal for this car?

Response From ImaStumped

To sum up where I'm at now, I basically have a "like new" car whose heating system functions "normally" (compared to two other cars I own) except at idle...at idle the temp dips to 116...

The water pump definitely slows down at idle...so the questions now are:

1. Is the problem an obstruction, or weak water pump? Possible, but given the "pristine" condition of the vehicle and the pumps ability to hold the engine temp rock solid, it's hard to accept.

2. Do I still have air in the system? Definite possibility...

3. Maybe this is "the way it is" for a 2005 Tribute? Last night, I noticed a neighbor down the street drives a Tribute!...I don't "know" him...but I did speak with him once as he walked past...I'm going to try and "walk past" his house and catch him outside...maybe I can see what his output temp is.

I'm also going to seek out a new shop, speak with the mechanic and possibly go with a vacuum flush and fill to definitely eliminate the air possibility.

Response From Hammer Time

Restricted heater core........................

Response From ImaStumped

HT, I've yet to see anything I could label "crud"...I mean nothing...normally the reservoir holds gunk...it's literally like new. I caught the water from the core flush in both directions...absolutely "crud less"...the engine is so clean I didn't even get dirt in that water...I mean nothing..

As I posted, it appears to functioning normally (compared to my two other cars) at all times except idle...I will continue to investigate.

Response From Hammer Time

OK, you keep looking then.

Response From nickwarner

When engine blocks are made, the molds are made of sand. The molten steel moves in and ends up with some of the sand in its pores. Heavy diesel trucks actually have coolant filters on them not only because it is a convenient way of adding the SCA they need but also to catch these pieces when you come loose in the cooling jackets of the block.

In cars, this stuff usually ends up in the heater core. It jambs in real tight and sets up. While you do have some flow which you can see with a garden hose, its not enough flow to give you the amount of heat you want. Your core uses a crossflow design, not a pass-through so water will only flow through the path of least resistance, maybe only using 1/2 to 1/3 of the total core to do so. You get flow, but not enough surface area for a proper heat transfer.

If you have some garden hose and a bilge pump, grab a bucket and some hose connectors that you can get at most any hardware store. Unhook the heater hoses completely from the engine. Hook one to the hose coming from the pump, the other to another length of hose returning back to your 5 gallon pail. Put a gallon of CLR cleaner in the pail and start the pump. Let it run for about 10 minutes and then swap the hoses to make it flow the other direction. I like to use clear vinyl hose that you can get at most hardware stores so I can actually see what is coming out. After you run if back and forth a few times, swap out to a different bucket full of hot water. Do what you did with the CLR, running at first one direction and then another. Might want to change the water out of the bucket halfway through or so. You'll know if its working because your flow will go way up. CLR breaks up mineral deposits, especially when it isn't diluted. Costs about $28 for a gallon jug. Bilge pumps for a boat that run off a 12v battery work well for the job. You can even get a cheap one at Harbor Freight that will work.

I've used that method to save a lot of blocked heater cores that would otherwise be a very time-consuming and expensive job. Its worth a shot to try to clear it this way.

Response From Hammer Time


The core is full of calcium buildup. Nicks idea is fantastic.

Response From nickwarner

I doubt its calcium unless this thing uses milk for coolant. But a 9 year old car with only 10k on it likely never got flushed before. So all the crap ends up in the core and plugs it up. If there is any rust holding together with the silica residue, the CLR method will break it up. Better than tearing out the dash to go after the core.

Response From Hammer Time

I don't know about the water up your way but the water around here it has minerals in it that leaves a crusty build up nearly anywhere is remains stagnant such as toilets, sinks, showers, heater cores and radiators.

Response From Discretesignals

Makes you wonder why we don't have kidney stones the size of golf balls.

Response From ImaStumped

Makes you wonder why we don't have kidney stones the size of golf balls.

For me, a 5 stage Reverse osmosis system cleans the water up real nice!

Also, scientists now suspect that kidney stones are actually the shells of super tiny microorganisms living in your kidney!

Response From Hammer Time

It might be under 10,000 miles but it's 9 years old and that's where the crud build up comes from. In fact the low mileage works against you.