Logo
FULL SITE MENU

Ruptured Heat Exchanger

S

stewsbs

Contributing Member
"I have an AQ131A and I Cant s

"I have an AQ131A and I Cant seem to figure out where my fresh water is going I fill the tank and let engine idle for 12 hour and tank stays full if I take the boat out for a 12 hour the water dissappears and boat starts overheating and slows down will not go over 3000 RPMI have checked all the hoses the water pump the thermostat housing around the head there is no water getting into the oil.I am running without a thermostat and using just water there is a slight leak in my raw water strainer but dont think that that has anything to do with it.Could I have a ruptured heat exchanger and when the pressure builds water is forced out and mixes with raw water,could it be escaping as steam through the radiator cap what rating should I get for a new cap.ANY HELP WOULD BE APPRECIATED THANKS!"
 
"Do you have an overflow tank

"Do you have an overflow tank installed? When installed properly, the line running from the radiator cap to the tank creates a closed system. I would also recommend running the proper glycol / water mixture.

To rule out a ruptured HE, I would pickup up a radiator pressure tester at your local auto parts store (Autozone has a great tool rental policy). Pump the HE up to 13 psi and see if it holds. If it does, begin to look elsewhere.

If you are only losing coolant when under load, you may have a blown head gasket. Pull your plugs and inspect them. Are any of them unusually clean, or white? Execute a compression test to determine if the gasket is bad.

Also, throttle down your engine immediately if you see the temperature spike. Trying to rev 3000 RPM with an overheated block is not good. Good luck."
 
no overflow and I do not have

no overflow and I do not have a pipe in the neck of the heat exchanger under the cap is there a cap with an outlet to rig up an overflow system?
 
"Yes, you could have a perfora

"Yes, you could have a perforated heat exchanger, but the problem could also be due to other causes. Start your engine, remove the expansion tank cap (radiator cap) and look for bubbles coming to the coolant surface. If bubbles are present, that's a sign of a cracked head or blown head gasket (usually the latter in your engine).

Also, I would replace the thermostat if I was in your shoes. Those little 4 bangers do not like too much cooling."
 
I have foam at the top and I j

I have foam at the top and I just replaced the head gasket last year would a cracked head have other symptoms that I would notice?
 
"The thermostat should atart t

"The thermostat should atart to open at 180ºF and should be fully open at 198ºF.

The radiator cap should be rated for about 5 - 7 psi.

When you replaced the head gasket, what torque did you use to tighten the head bolts? Also, did you make sure before installing the head gasket that both the head and block surfaces were completely clean and that the head was not warped?"
 
I had my mechanic do it I assu

I had my mechanic do it I assume he checked the head and I know he used the specs in the Clymer book for head bolts although we did not retourque the bolts after running engine for awhile.Is there suppossed to be an overflow system because like I said I do not see a nipple in the throat of the heat exchanger to attach a hose for the overflow?
 
Think the foam came from filli

Think the foam came from filling with the hose I will check tonite now that it has had time to settle will check then start up engine to see if I get air bubbles.Correct me if I am wrong but wouldn't a warped head or cracked head and or blown head gasket give me water in the oil also?
 
"Stewart, there is more than o

"Stewart, there is more than one torque setting for the OHC Volvo 4 cyl engines, depending on whether you have hexagonal or Allen bolts. The ones with Allens I recall you torque them to 15 ftxlb, then 30 ftxlb, then another 90º. See attached instructions from one of the gasket sets I used in the past.

A warped head may or may not give you water in the oil; in fact, it may not give any symptoms at all. However, a good sealing is more difficult to achieve with a warped head.

171873.jpg
"
 
"I had a Toyota truck with a b

"I had a Toyota truck with a bad head gasket. I ran it for 30K miles w/o ever getting water in the oil. I would, however, continually add glycol and the plugs always indicated a cool burn."
 
Thanks for all the info gettin

Thanks for all the info getting this engine running right to the point that I trust going more then a mile from the dock is driving me nuts I will double check the torque I have hexagonal bolts and I correct that there is no overflow system on this particular engine?
 
 
El I hate to sound like an idi

El I hate to sound like an idiot but after looking at the schematic of the heat exchanger I am confused it looks to me like the raw water is kept isolated in the insert and that the anti freeze is just in the housing or radiator if that is how it works how could a hole in the insert explain my loss of anti freeze wouldn't the hole have to be in the housing or what I am calling the radiator?
 
"Stewart:

Yes, a hole in th

"Stewart:

Yes, a hole in the heat exchanger (8) could explain the loss of coolant, but a hole in the heat exchanger also could fill your tank rather than emptying it (at least while the engine is running).

It seems to me that you have been given some good leads regarding where/how to troubleshoot your problem. Mike suggested that you start pressure-testing the system, and I additionally suggested that you check for bubbles to discard (or confirm) combustion gases reaching the coolant. If you want o check for a hole in the heat exchanger, use Mike's suggestion and if the pressure drops remove the copper pipes connecting to elbows 22 and 18 and look for coolant: if you find it, then you know that most likely your heat exchanger is perforated.

Now I think it is time for some troubleshooting action on your side."
 
Finally got out to work on the

Finally got out to work on the boat first thing I did was retorque the head as it was done at the lower spec pulled the plugs and clynders 2 and 3 were very clean after retorque I checked for bubbles in heat exchanger there was a few not like before I warmed up the engine and pulled the plugs again the 2&3 cylinders now look like they are getting blacker had to order a thermo could not find one locale did a compression test and results were 145-150-150-153 so I think that is ok unfourtonatley the alternator crapped out on me so I could not take the boat out to see if the heat exchanger still emptied out of fresh water.I should get my new thermo this weekend as well as the new alternator will install and replace thermostat housing gaskets and will let you know the results.Thanks for all the help and great info!
 
Back
Top