orsogrigio

Hi guys, here Iam again with a doubt about one thing that happen some time ago. I have replaced many parts in the cooling system (Water pump, thermostat, fan clutch) exept for the radiator hoses that have been replaced when car arrived in Italy two years ago: Well, every time I used the car I had to refill the reservoir, but I haven't seen any cooling liquid leaks (when car arrived I removed the heads and resealed with new gaskets), so I asked my mechanic what problem could be, and he said to replace the radiator cap with a new one, so I did, the old cap was 13 lbs, and the new is 16 lbs. With the new cap the liquid do not evaporate as with the old one, butthe first time I drove the car on motorway at high speed the lower hose exploded, so I replacet both lower and upper ones, and everything seems go well until I took next time I drove the car on motorway at an higher speed. The fan has cutted the upper hose, I don't know why as I placed the new like the old that I substituted. the temperature has not gone higher as it should, but since then I do not feel the motor runs as it should

orsogrigio

One thing I miss to say, the liquid reservoir is not a factory issue but has been added by the first mechanic that worked on the car when arrived from USA

oldcutlass

Seems to me your cap is still an issue. You need a cap, lower pressure applicable to an overflow tank, that lets fluid in and out as needed.

The other issue may be that your thermostat is not working properly and not opening up. Let the car warm up with the cap off and make sure you have water flow in the radiator.

orsogrigio

I replaced thermostat some months ago, I do not remember if opening 180 or 160 degrees, the fan clutch is starting 160°, before replacing the clutch the temperature went over 180° but since I replaced it the temp stand at 180°, the only problem was that the liquid reservoir needed to be refilled almost every time I used the car, The new radiator cap I placed is 16 lbs when the old was 13 lbs, and the liquid stand as it should, but when I used the car at 70 mph the almost new lower radiator hose has broken, now, is it possible that a higher cap pressure can do that? Maybe the hose presented some hidden factory flaws, as my mechanic says that if they work as they should they must resist to a 30 lbs pressure: it seems that the thermostat works as well as it should, as the engine warm quick and the temp is stabilyzed at 180° and do not overheat, but I will follow the suggestion to let warm the car without the radiator cap

oldcutlass

Some times when a car overheats due to a thermostat, the gauge does not show a hot condition. However it will burst or blow a hose off. The cap pressure is of no consequence but it must be for a reservoir system to allow fluids in and out of the radiator as needed. Most older cars used a closed system with no overflow tank. A blown head gasket would cause a similar situation with possibly an overheating issue, but lets rule out the easy checks first.

jaunty75

Changing from a 13 to a 16 lb cap certainly raised the pressure in the system, so anything that might have been iffy at 13 lbs could have blown at 16, so, yes, I would say that changing to the higher-pressure cap could have caused the hose to blow. But your mechanic is right in that the hose should be able to handle 16 psi pressure with no problems, so the hose was likely weak to begin with in spite of the fact that it was new.

One other possibility, I would guess, is that the 16 lb cap is defective and didn't open at 16 lbs but rather stayed closed and allowed the pressure in the system to exceed 16 lb and blow the hose.

orsogrigio

I'm gonna check warming the car without the cap if fluid flows, but when we placed the thermostat we tested if it works squeezing the upper hose and it seems fluid flows into it, and it seems to me to remember with the cap off also (not sure). It's possible the cap is defective and does not open at 16 as it should, I replaced the head gaskets when the car arrived, but when the fan cutted the upper hose (don't ask me what happened 'cause I really don't know), coming back from a trip when I arrived into the garage, I heard a strange noise as something that touched under the hood, so I opened it, and it seemde coming near the fan, so I tested with the engine off of course and moving the fan it turned free and did not touch anything, and, again, there was not the way to suspect something wrong about it because the hose was placed correctly, then, I visited the mechanic the day after to control the problem, but the noise had disappeared and seemed everything work right, and in the evening Iwent out with the car for about 80 miles, the noise reappeared, I stopped to control, and... nothing seemed wrong and I started again, but when I stopped to pay the ticket at the pay check a consistent amount of steam came out from the hood and seemed that the whole car took fire, so I switched off the engine and open the hood, It was the cooling fluid that came out from somewhere, and with a lamp I found that was the upper hose cutted by the fan, and I refilled the radiator with about 1 and a half gallon of water, but the gauge did not shown a overheating, just the car did not runs good. Now seems run well, no cooling fluid mix the oil, but anyway I'm not sure that the fact has not caused damages at the heads

455man

Check your motor mounts. If one is bad the engine might twist and the fan could move up to cut the hose...but do you have a fan shroud? Usually the fan will cut the shroud first before getting to the hose.

jfb

I do not no how long it sits but some coolant does evaporate in time. I have a 16 pd cap also but it helps me and helps temperatures and i have had no issues also check your motor mounts for movement this could be your cause of the hose cutting,extrem movement i mean.

orsogrigio

I replaced the motor mounts at the same time I replaced the fan clutch, the timing chain, the thermostat, I don't know what is the shroud, may be the black plastic protection that surround the fan fixed at the radiator? if so, yes it is on place, is there that there is a sort of clip that block the upper hose to avoid it moves, the clip tie the hose to the shroud with a screw (sorry, I'm not sure I'm using correct terms). Maybe changing the motor mounts the whole motor stay higher and so do the fan, and when accelerate may be the engine have a pitch or rear up and so the fan could have cut the hose, but this has been resolved with a little distance bar that keep the hose afar from the fan, what worrie me is the loss of fluid that could have damaged the heads, even thou, I have not found fluid bubbles in the oil dipstickand neither mudd in the radiator cap, all things that make sure a burnst of the head gaskets

GreekDog

I had a similar problem with my car. I kept losing radiator fluid but it wasn't visible from a specific location.

I ended up replacing the water pump, clutch fan, and I had my mechanic flush out the radiator because it was LOADED with build up from the previous owner.

I would suggest checking if their is gunk in your actual radiator.

orsogrigio

When I placed the thermostat (when car arrived the thermostat was missed, probably removed by the previous owner) we let the engine runs with water loose so the radiator has cleaned up, the water pump works with no rattles, I have a new one still packaged but the mechanic says there is no reason to replace it 'cause it works well, about the problem of the fan that cutted the upper hose, probably the motor mounts are not placed sharp, I will control with the mechanic that makes the job if everything it's alright. I want to thank all you guys that answer to all my questions, it's beautiful to know to have friends even if unknown in person so far away from home. It's very hard to mantain in life 40 years old cars born at the other side of the world and give 'em or at least try to give 'em a new life and only love can push a man to spend the most of his time to take care these old heaps

MDchanic

I would recommend getting some objective information to help figure this out.

You should pressure test the cap and the system with a pressure testing tool (most mechanics have them), to be sure that the cap is working properly and that the system doesn't have any leaks.
After that, you will have a better idea of where you stand.

- Eric

droldsmorland

Are you sure the thermostat is installed in the correct position/direction? If the T-Stat is installed backwards this can cause excessive pressure at highway speeds (most of the time). To blow a hose either the hose was bad or there’s a buildup of excessive pressure due to a blockage. Maybe a gasket was installed incorrectly?
Next you need to pressure check the cooling system. A special device is installed where the radiator cap goes onto the neck of the radiator. This device allows you to pump up the cooling system with a hand held pump connected to the radiator. It has a pressure gage on it. Pump it up to 15-20 psi, maximum. If the system does not hold that pressure for at least 10 minutes you have a leak somewhere. Pull the spark plugs before you preform the pressure check.
With the spark plugs out bar the engine over with a breaker bar in the direction of normal rotation. If you see coolant shoot from the cylinders you have a blown head gasket or a cracked casting either on the head or in the block.
The coolant has to be going somewhere. If it’s not leaking externally then it’s either entering the combustion chamber and being burnt off or leaking into the oil pan. Does the exhaust smell like coolant? Is the oil milky? Look at the spark plugs for evidence of burnt coolant or the odor of coolant.
If the fan is not centered in the plastic fan shroud you may have miss-matched engine and or transmission mounts? The shroud directs air flow and is an important part of the system. It should be present and in good shape.
I agree with others that a 16 psi cap is too high. I run a 7psi cap. Don’t be afraid to invest in a high quality T-Stat (195*F) and a high quality cap.
Let us know when you find the problem.

orsogrigio

Hi guys, I wanna thank all of you that answer to my thread, I let go these xmas days and I go visit the mechanic, He's a good one with experience with every kind of vehicles, he has rebuilt a Dodge Charger engine for another guy in the place. the only thing that I do not quote for him, is that I must point a gun to his head to make him work, 'cause while is working on a car, it arrive a guy with a problem and he let what is doing to check him, so, arrive another and is the same, but all the jobs he make work good, the problems happened with this new cap, and maybe the upper hose has been cutted 'cause the new mounts lifted a little bit the engine and the new hose I replaced was a little longer than the old one, but after all the controls I'll have a better view of the problem.
Merry xmas to all you guys and thank you for all

MDchanic

Buon Natale, Orso!

E auguri per l'anno nuovo.

- Eric

oldcutlass

^^^^^^^^^what he said.

orsogrigio

hello boys, have you had good holidays? I visited the mechanic for my coolin' system problem, well, there was a little leak in the radiator, so I remove it and send it to the radiator specialist that have sealed the leak and cleaned it, but now the weather is bad and I can't test the car, but when I bring it home from the mechanic garage it seems everything alright. He tested if there was a blown head gasket, without pull the spark plugs, but he said the head gaskets are alright 'cause the cooling fluid has not changed colour, so no exaust gas has mixed to the fluid. Well, the first sunny weekend I bring out the car for a ride

oldcutlass

Let us know how it turned out and glad you made it through the holidays also.

fbonanno

I agree with drolds. If your not overheating, run a lower PSI cap. I am running a 7 PSI cap because my radiator has a slight leak on the top end. High pressure on the system is only needed when and if you approach over temp.