Jump to content

Boiling Over


nigelt

Recommended Posts

Hi All,

 

I have a strange problem in that my engine is boiling over quite violently. I don't have an expansion tank so first thought that this might be the problem. Then I thought that I might have a stuck thermostat, (only to find I hadn't fitted one). I'm now thinking that the water pump has packed up. Does this sound likely? before I start pulling it all apart. The lump is 1800 CVH.

 

 

Nige

Link to comment
Share on other sites

Hi Peter,

 

No I'm pretty sure its not the Head gasket, all compression test are good and I'm not getting any bubbles in the system. But I might check again just to be sure.

 

Thanks

Link to comment
Share on other sites

Having checked out the flow tonight. I noticed that while the engine was warming up, the level in the radiator kept rising and falling. Then before the fan came on which is at 88 deg, the rad overflowed. With the Cap on the water comes out the overflow on the rad, even though I have the original overflow pipe from the thermostat housing going to an expansion bottle. I would not have expected the cap to rise if there is an easier route for the water to expand out of. I have to say that the expansion bottle is not then fed back into the lower rad pipe, its more of an overflow bottle.

 

I have checked the compression on all cylinders when hot and this is about 116psi quite low compared to what it should be (150 - 180psi), but not sure if this is about right for an engine that has done 188,000 miles. I'm also certain this was the pressure before all the boiling over happened.

 

what makes me think it might be the pump, is I used to get a screeching noise from the engine when it first started up, but went away quite quickly, but now it doesn't make that noise. around the same time I noticed it starting to over flow. (I won't say boil over as its not got that hot, so its an expand over)

 

I have some photos but not sure how to attach them, as the option to attach files limits me to 100K, is this the right way?

 

 

Link to comment
Share on other sites

What cap have you got on the rad?

If it overflows that easy the pressure section in the middle may be weak

You have a hybrid system, expansion bottle and header tank

You should have one or other, with the way you have it there is no pressure in the system

Block small pipe from pump and see if rad holds pressure longer

Also check you have correct rad cap for expansion set up

 

OR

 

Run overflow to header tank with small pipe from pump still connected and see what happens

Edited by Snapperpaul
Link to comment
Share on other sites

Guest mower man

As said on a different thread water pumps either work or they don't in the 50years I have been involved with theit made infernal comb engine only one failure comes to mind ,the impeler fell off the pulley shaft ,it made a hell of a noise I suppose your squealing noise that went away could be the same . reading your post and having run a cvh a while ago head gasket would be first port of call if water is being expelled in any amount what is causing it ? my bet is a weepy head gasket . In my op a suck and blow system seems to work as good as any thing , cant see the sense in to the system you have described mowerman :crazy:

Link to comment
Share on other sites

Thanks Guys,

 

I'm not running an expansion bottle as it was on the sierra, in that it expands into this and feeds back via the bottom hose. The main reason for that was room, I don't really have much room anywhere to put the bottle higher than the auto' choke. All I have is the overflow bottle. The idea being that in the event of an overflow, coolant didn't end up all over the floor. However, I didn't think that one through too well, in its implementation, as it blew coolant all over the engine bay. So I am running the piping just as it was on the sierra except for the expansion bottle and using an over flow bottle instead. The pipe that did go to the expansion bottle I originally had blocked off, but then changed that to flow into the overflow bottle which is mounted lower down. Here is one of the photo's which looks rather large so only attached the one. The small black pipe going off to the left is the overflow/expansion pipe which has been temporarily disconnected in this photo. Inside the thermostat housing it has a one way valve, (well a ball bearing to be precise).

 

The radiator cap is the one that came with the kit so not sure at what pressure it lifts at but must be low or faulty as suggested.

 

Nige

 

20140319_220410_zpspezwn0xi.jpg

 

 

 

20140319_220410_zpspezwn0xi.jpg

Link to comment
Share on other sites

If you're feeding an overflow bottle from the thermostat housing (the pipe above the temp sensor in your picture?) then you have an open system and it will boil as it isn't building up any pressure to raise the boiling point.

You need to block that pipe by fitting a bung or a bolt and move your expansion bottle to the pipe coming off the radiator filler. The system should then pressurise, the boiling point will be higher - around 120 degrees and any water expelled as it expands will be sucked back into the system as it cools.

Link to comment
Share on other sites

Ah ha, now that's how I had it plumbed originally, but maybe the rad cap is failing and lifting too soon. However, does it get sucked back in when it cools as the cap will close?

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...