Coolant thumping after shutdown

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Joined
Aug 13, 2010
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Location
Conway, S.C.
My Car
1972 MACH 1
2019 F150
Orderd and installed a restictor under T-stat with no help:huh: Thumping still and loud for few minutes at waterpump area. Temp gauge never reads hot before or after change. Hear and feel thumping like air pockets like coffee pot but way every shutdown? New 3 core rad. and waterpump.

Alan L

 
No reading on your temp gauge is a dead give away that there is air in the system. Did you replace your radiator cap? What kind of radiator cap do you have?

You might try a cap with a pressurized vent release and then when it heats up a little, carefully(with gloves) slightly lift the lever and release some pressure.

Be very careful cause it wil burn you quick! Maybe even have a towel between your gloves and the cap. This will get any air out of the system, if that's the issue.

Be careful!

 
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Orderd and installed a restictor under T-stat with no help:huh:

Alan L
My regrets you are still having an issue. Hate it when the Mustang has gas. In the old days, that is how you separated the plow horses from the buggy horses...

Okay, so you still have a hot spot.

1. Did you get the restrictor with the large hole, or did you get the restrictor with the tiny hole?

2. If you got the restrictor with the large hole, do you have a photo of the spring side of the thermostat? Do you have the make/model?

Regardless of restrictor type,

3. Did you check your thermostat by filling your your wife's best boiling pot with water, putting the thermostat in it, and watch the thermostat open prior to the water boiling? If you have a meat thermometer you can measure the actual temperature of the thermostat opening.

4. To assure your system is circulating water, have you taken off your radiator cap when the engine is cold, start the engine and confirm the water is circulating? Again, your wifes best meat thermometer can serve to measure water circulation temperature.

You will lose some water, maybe a pint when you do this. Some people like to put cardboard over their radiator to keep the motor hot. But some of them forget to remove the cardboard. Don't forget to remove the cardboard.

5. Once the car is warm, are your heater hoses hot? Do you get hot air in the car?

We'll get this licked, if it costs you every dime you got.

 
1. Took a large open resticter out new one is solid with small pin hole.

2. new 192 Tstat with short spring

3. two sets of gauges tried, both read 195 after warm up.

4. heater hoses DO get hot.

5. new 3-row alum. rad. with stock 4-blade fan.

6. new water pump with rebuild.

7. can see coolant flow inside radiator.

8. will try new cap old one had split gasket, new one cheap.

Alan L

 
My engine did that after the rebuild. Check this...look at the head gaskets where the block meets the head in front.. there should be a TAB sticking out ,,,on both sides.

The gasket WILL go on backward ask me how I know, lol

 
The restrictor should look like this. http://351cleveland.wetpaint.com/page/Brass+Bypass+Washer

The correct thermostat should look like the second large picture. http://351cleveland.wetpaint.com/page/proper+351c+thermostat

Does the engine over heat/puke coolant? Do you know what temperature it gets to? Chuck
There is a theory from the 335 Forum aka Pantera group that the OPEN BRASS bypass does not seal to the thermostat when the engine gets warm, causing the water in the heads to only circulate through the water pump and not the radiator, causing overheating.

Their cure was to basically override the bypass by sealing off this opening. The down side of this solution is the heads do not get water circulated during cold starts. The up side is you are certain to have good circulation once the thermostat opens.

In an effort to cure his problem on a previous post, it was suggested to either make sure he has the right thermostat for the OPEN BRASS seat, or to implement the Pantera group method.

Now that he has implemented the Pantera method, and answered my previous queries, it seems he does in fact have good circulation, I am kind of stuck on what else he can do.

A weak radiator cap would decrease the boiling temperature of the water, but I don't know how to test the radiator cap.



The gasket WILL go on backward ask me how I know, lol
Never would have thought of that.

 
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A weak radiator cap would decrease the boiling temperature of the water, but I don't know how to test the radiator cap.
You need a radiator cap/radiator pressure tester. The cap goes onto a tube that you pump up with air. You can check at what pressure it starts venting and also how fast it leaks down:

http://www.amazon.com/gp/product/B0002SRGWU/ref=pd_lpo_k2_dp_sr_1?pf_rd_p=486539851&pf_rd_s=lpo-top-stripe-1&pf_rd_t=201&pf_rd_i=B002DQOHA8&pf_rd_m=ATVPDKIKX0DER&pf_rd_r=0HZXPJ10SP8BKG492VHH

Wow, what a link, hope it works...

 
You need a radiator cap/radiator pressure tester. The cap goes onto a tube that you pump up with air. You can check at what pressure it starts venting and also how fast it leaks down:
Wow...I have seen testers for the cooling system, but not one for the cap.

Link worked...and only $70...(choke choke)...though that seems reasonable. I always wanted to be able to check my radiator caps, especially right after I bought them.

One of the reviews indicates you may need a pricey adapter to fit your radiator cap.

One of you guys can get me one for Christmas. Make my day.

 
Here's a thought. We used to remove the thermostat and run washers with the proper size hole for what we doing with the car. When racing on the weekends I would change the washer to a larger diameter to accomodate the thumping I was giving it. If I forgot, I percolated like hell to remind me. And good diagnostic tools save thousands!!!

 
My engine did that after the rebuild. Check this...look at the head gaskets where the block meets the head in front.. there should be a TAB sticking out ,,,on both sides.

The gasket WILL go on backward ask me how I know, lol
That was my first thought since I once (only once) installed a head gasket backwards.

 
Again, the coolant temp runs normal @195 all times never running hot cruising or at idle. Also the temp sensor screws just babove the waterpump/timing cover in the same area as the thumping. Also saw no tabs front or rear on headgaskets.

Alan L

 
Again, the coolant temp runs normal @195 all times never running hot cruising or at idle. Also the temp sensor screws just babove the waterpump/timing cover in the same area as the thumping. Also saw no tabs front or rear on headgaskets.

Alan L
So I am guessing that the new rad cap didn't do it?

A little late now, but the heads gaskets are both marked FRONT, One side the wording goes down facing the block, so it looks wrong at first glance because it is not identical sitting on the engine. The other side is upright facing the head. If it is backwards, you will block the water outlet to that head, but it will still flow to the other side.

If the weather gasn't been that hot, the engine temp may not be effected until you start getting 80-90 ambient.

 
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Once the t-stat opens and engine shut down the thumping is inside the waterpump impeller area.

Alan L
This is really bugging me.

If the cooling system is filled with water AND if the thumping is water boiling, the VAPOR the water is making should force water out the out the thermostat.

Are you topping off your radiator?

 
Took a 20minute ride lastnight and pulling into the garage and shutdown blow all the coolant out from lower rad. hose or waterpump. Not sure which but will findout on friday my day off.

Alan L

 
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