Click here to return to the home page.
Image of a road.
Who's Online
13 registered (Budster, planenut, Ncik P, BobtheTrain, Jens, mise303, LightSpeed, Q8morgan, Chris99, jrt, SimonH, OZ 4/4, Michael H), 134 Guests and 13 Spiders online.
Key: Admin, Global Mod, Mod
Latest Photos
Southern Weather comes North
Island of Muhu in the rain
65 Plus 4 Four Seater back seat Lift-a-dot studs
Fuel cap seal
Touring Scotland with Anglemog.
Newest Topics
Mog19
by DaveW
17/06/19 10:53 AM
Shenandoah annus primus
by rcmatt
17/06/19 12:34 AM
Four-seater rear wing reflectors
by Soleng
16/06/19 09:50 PM
Slowly increasing idling in 3L V6
by BertR
16/06/19 09:46 PM
Funny road in China
by Jens
16/06/19 08:40 PM
Duratec - swirl flaps ?
by teknome
16/06/19 08:03 PM
FOR SALE : SEALEY ELECTROSTART®
by James B W
16/06/19 05:06 PM
Newest Members
arnieb, BradB, PANTHRO, MarsdenRobinson, M500
6524 Registered Users
Shout Box

Forum Stats
6,524 Registered Members
33 Forums
35,380 Topics
570,877 Posts

Most users ever online: 341 @ 11/02/18 10:30 PM
Today's Birthdays
No Birthdays
Topic Options
#580612 - 10/06/19 12:27 AM Diagnosing an Overheating '68 4/4
BradB Offline
New to Talk Morgan

Registered: 25/05/19
Posts: 4
June 9, 2019, Ottawa, Canada, 30C(86F) outside. Wanna-be mechanic here. I have my Dads '68 4/4 a long way from home.

Unfortunately I happily drove 400km with the thermostat reading 70C --- the ambient temp outside was only 5C but eventually suspicious I checked the coolant to find that the reservoir was empty. I hadn't checked it before I embarked on this trek (sorry everyone) - topped it up for the last leg of the drive, into the city, and now the temp gauge is reading 110C. I reached my destination, checked that coolant was at the top of the radiator cap and then I noticed a pin hole leak at the top of the rad (in the top reservoir part).

The aluminum Marston Excelsior radiator had sprung a pinhole leak before or after I stated the trek and (coincidentally?) the engine is now overheating into the ~110-115(230-240F) degree Celsius range (according to the temp gauge and an infrared thermometer on the top of the rad). I can fix the leak but in the meantime I want to diagnose the overheating. I don't think the pinhole leak in the rad is my problem (or is it?).

The water pump visually looks good. No leaking.
I removed the thermostat for the second test run and also tested it to find that that it operated normally in a test bath.

I've removed (to find the hole), flushed and refilled the rad, and am not losing enough coolant from the pin hole in the 30minute test-run time, to get up to temperature, to need or be able to top it up.

First test: after I flushed and refilled the rad with deionized water, I let it idle for 20 minutes (maybe not long enough) and it peaked at 90C. Seemed good enough for a test drive.

Second test: Driving through downtown up to Rideau Hall, 40 minutes, 30C ambient temperature, thermometer goes up to 90C then after 30 minutes-from-cold, up to 110C, back to 100C... I put the heater on when the thermometer got to 100C.

I'm going to seek professional help now but would like to hear if anyone has any ideas.

Thanks,

Brad
'68 4/4
Engine: V-Comp, 116E GT, Ford Cortina
Radiator: Marston Excelsior
Water pump: Lucas 22716N



Edited by BradB (10/06/19 12:47 AM)

Top
#580614 - 10/06/19 01:29 AM Re: Diagnosing an Overheating '68 4/4 [Re: BradB]
Uther Offline

Learner Plates Off!

Registered: 08/01/16
Posts: 471
Loc: Australia
Have you checked for mayonnaise in the rocker cover or radiator, which might indicate a head gasket failure? Hopefully that’s not the case but for the time you ran with the empty coolant reservoir the temp could have been sky high at the head.
Hope all goes well , cheers John
_________________________
Cheers John
2011 4/4 - "Elrond"
67' Lotus Elan S3 Coupè "Emma"
68' Lotus Type 51a FF "Emerson"

Top
#580634 - 10/06/19 08:17 AM Re: Diagnosing an Overheating '68 4/4 [Re: BradB]
TBM Offline
Learner Plates Off!

Registered: 06/11/18
Posts: 494
Loc: Northants, UK
Things I'd check:

1. Water pump - make sure it's actually working. Remove a hose to see what the flow is (heater hose is good). Take care - the water will be very hot and only do it for a second or two but shutting engine off.

2. Air lock - you may have an airlock in the system that needs bleeding out.

3. Compression test - may show any headgasket problems.
_________________________
1972 4/4 4 seater
Too many ratty motorbikes

Top
#580661 - 10/06/19 12:02 PM Re: Diagnosing an Overheating '68 4/4 [Re: TBM]
tmg513 Offline
Talk Morgan Enthusiast

Registered: 27/08/08
Posts: 1985
Loc: Powick
Originally Posted By TBM
Things I'd check:

1. Water pump - make sure it's actually working. Remove a hose to see what the flow is (heater hose is good). Take care - the water will be very hot and only do it for a second or two but shutting engine off.

2. Air lock - you may have an airlock in the system that needs bleeding out.

3. Compression test - may show any headgasket problems.

As the temperature went up after it was topped up, I'd suspect an airlock as well.
_________________________
1972 4/4 2 Seater

Top
#580665 - 10/06/19 12:40 PM Re: Diagnosing an Overheating '68 4/4 [Re: Uther]
BradB Offline
New to Talk Morgan

Registered: 25/05/19
Posts: 4
Thanks, John. No mayonnaise in the rocker cover, rad or oil dipstick. I did drain some oil too because it was overfilled last oil change, and that looked dark but not unusual. I will do a compression test to double check the head gasket.

Brad

Top
#580683 - 10/06/19 01:43 PM Re: Diagnosing an Overheating '68 4/4 [Re: TBM]
BradB Offline
New to Talk Morgan

Registered: 25/05/19
Posts: 4
Thanks for the suggestions, TBM

1. Water pump check - can I do that with the engine running and cold? That's what I did. There's not a whole lot of pressure or suction but it is flowing. I disconnected where it comes out of the heater first and the flow was less than when I checked the hose going in to the heater. The thermostat has been removed. I made a video recording of the result https://youtu.be/CQTs_J-ky5o

2. Will look into the air lock next.

Thanks again,

Brad


Edited by BradB (10/06/19 02:02 PM)

Top
#580766 - 10/06/19 08:55 PM Re: Diagnosing an Overheating '68 4/4 [Re: BradB]
TBM Offline
Learner Plates Off!

Registered: 06/11/18
Posts: 494
Loc: Northants, UK
Personally, I think that looks a little weak but the pump is definitely working. It could be an airlock that's causing a depleted flow....

Water pumps are cheap, and an easy replace, so might be worth replacing it.
_________________________
1972 4/4 4 seater
Too many ratty motorbikes

Top
#581070 - 12/06/19 02:45 PM Re: Diagnosing an Overheating '68 4/4 [Re: BradB]
BradB Offline
New to Talk Morgan

Registered: 25/05/19
Posts: 4
Originally Posted By BradB
Thanks, John. No mayonnaise in the rocker cover, rad or oil dipstick. I did drain some oil too because it was overfilled last oil change, and that looked dark but not unusual. I will do a compression test to double check the head gasket.

Brad

I did a block test and it showed no combustion gas in the coolant.

Brad


Edited by BradB (12/06/19 02:46 PM)

Top
#581071 - 12/06/19 02:51 PM Re: Diagnosing an Overheating '68 4/4 [Re: BradB]
Hamwich Offline

Talk Morgan Guru

Registered: 28/04/08
Posts: 7546
Loc: Gloucestershire, UK
Are you sure the car actually is overheating and it's not just the gauge reading high? Check the gauges are all earthing properly.
_________________________
Tim H.
1986 4/4 VVTi Sport, 2002 LR Defender, 1957 R4 CV, 2005 Ferrari Vipar

Top
#581113 - 12/06/19 06:54 PM Re: Diagnosing an Overheating '68 4/4 [Re: BradB]
Graham, G4FUJ Offline
Salty Sea Dog
Member of the Inner Circle

Registered: 03/07/07
Posts: 22265
Loc: Cheltenham, Glos. UK
Should this thread not be in the Maintenance and Servicing section?
Just a thought... smile
_________________________
Graham (G4FUJ)

D8921 L44FOR '93 4/4 Giallo Fly 2 seat smile
'90 LR 90 SW
'07 MINI Cooper

Top

Moderator:  Aeroman, Boshly, Simon