Coolant question (core or freeze plugs)


(Tigger) #1

Coolant question.

Engine out full rebuild approx 5000 miles. All good.

Coolant level generally stable with usual top ups / spit out excess.

After no idea how long noticed rad cap upper seal was missing.

Replaced cap with new…

… now coolant loss…

Not via rad cap (no streaks / tell tales).

No tell tale of head gasket leak in oil cap / on dip stick.

Checked hoses (limited to those accessible from front / above.)

Noticed crescent of rust sat on the upper lip of the hose where vertical larger diameter hose connects to water pump, a few shiny sticky streaks running down the hose.

Volume of loss is around 3 pints after 200 miles.

Have yet to test after tightening but would a tiny ‘pee’ leak drop such a volume – as I write, answered my own question; of course it could…

Checked again better light this morning, found wet rusty sludge from central core plug….

Sure I’ve read of a sealing core plug design with tightening bolt – comments please.


(Paul Saltwick) #2

Search archives for “Dormann Core Plug”, and you will find all you need.


(Tigger) #3

Thanks Paul.

Not available in the UK as far as I can find; have asked a US friend to see if he can obtain and forward the Dorman items and if so will ask usual mechanic to fit. Closer examination shows the current plug fitting is about flush with the block surface in the lower right hand edge, so it might just need another thump in!

Part number 568-011 Dorman DC-11 1-3/4" Copper Expansion Plug and your comments noted re sanding to get snug fit and using epoxy before fitting / tightening.


(Tigger) #4

Hi Paul,

Might I ask you to confirm / clarify a couple of points? Please understand I have to contend with the British technician.

  1. The Dorman plug should fit flush with block before tightening?
  2. The sanding / emery is to adjust diameter not depth?

Thanks as ever,

John.

Bonus; pack of five plugs being posted to me by a friendly colonial of Delafield, WI tomorrow.


(The Jag Man) #5

What PSI radiator cap are you using? Way too might pressure could have an effect on leaks. Others please chime in.

Gerard


(Tigger) #6

David Manners supplied 4lb;

I’m concerned the plug is not recessed enough or the settled gunge has rusted away a bit of the block; there is no lip I can detect with my finger - the lower right edge of the plug feels to be flush with block surface so another thump might solve it.


(Tigger) #7

Booked in with Bob Bate for the 30th. Those who receive the Jaguar Enthusiast Club magazine will know Bob as the contributor of regular technical articles.

Hopefully all will soon be well…


(Paul Saltwick) #8

Tigger2
Tigger

    January 21

Hi Paul,

Might I ask you to confirm / clarify a couple of points? Please understand I have to contend with the British technician.

  1. The Dorman plug should fit flush with block before tightening?
  2. Yes, follow the instructions, only turn it by the number indicated.
  3. The sanding / emery is to adjust diameter not depth?
  4. Yes, my experience is they are slightly oversize. Resist hammering and I use a little expoxy sealer.
    Thanks as ever,

John.

Bonus; pack of five plugs being posted to me by a friendly colonial of Delafield, WI tomorrow.


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In Reply To

Paul_Saltwick

    January 21

Search archives for “Dormann Core Plug”, and you will find all you need.


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(Ed Nantes) #9

The manufacturer of the original lens shaped core plugs has an info page on its site. Installed correctly they claim good for 1400 lb. The proviso being installed correctly, something rarely seen these days.
Which also leads to material, they don’t recommend barrel plated steel, Brass core plugs are available for a dollar or so more. It may have made economic sense to Bill Lyons to save a pound or two per car when he’s churning them out. But not to me if you are going to be the one replacing them in the future. I prefer the “ do it once. Do it properly “ motto.


(Rob Reilly) #10

Here it is:
https://www.hubbardspring.com/