Keep blowing hoses off, now core plugs, what’s wrong here?

Keep blowing hoses off, now core plugs, what’s wrong here?

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gramos

Original Poster:

31 posts

127 months

Saturday 8th February
quotequote all
I replaced my water pump with a Davies Craig electric pump to help cooling in a hot climate . Lately when out driving when I give it the beans either a hose has blown off or recently 2 core plugs have popped out . Engine is recently rebuilt and special attention was paid the cleaning the waterways in the block plus a new alloy head was fitted . Also fitted is an alloy rad and electric pusher fan and new correct sleeve type thermostat. There is a new heater unit which has been tested and flows well . It seems ok unless its being booted , which is taking the pleasure ! Engine is Austin Healey 100 4cylinder 2.7l

BertBert

20,289 posts

225 months

Saturday 8th February
quotequote all
Head gasket?

E-bmw

10,957 posts

166 months

Saturday 8th February
quotequote all
Get a compression test done & see what it shows.

Also a leak-down test.

It is entirely possible that combustion gases could be over-pressurising the block/coolant ways.

CoolHands

20,671 posts

209 months

Saturday 8th February
quotequote all
Something cracked

LarJammer

2,326 posts

224 months

Saturday 8th February
quotequote all
What pressure rad cap is fitted?

gramos

Original Poster:

31 posts

127 months

Saturday 8th February
quotequote all
Cap is .7 bar/ 10 psi , spec says 7 psi

gramos

Original Poster:

31 posts

127 months

Saturday 8th February
quotequote all
Compression test results 170/175/175/172 happy with that 😁

TwinKam

3,321 posts

109 months

Saturday 8th February
quotequote all
I'd be doing a (hot) leak-down test and testing the coolant for combustion gases.

gramos

Original Poster:

31 posts

127 months

Saturday 8th February
quotequote all

stevieturbo

17,746 posts

261 months

Saturday 8th February
quotequote all
gramos said:
I replaced my water pump with a Davies Craig electric pump to help cooling in a hot climate . Lately when out driving when I give it the beans either a hose has blown off or recently 2 core plugs have popped out . Engine is recently rebuilt and special attention was paid the cleaning the waterways in the block plus a new alloy head was fitted . Also fitted is an alloy rad and electric pusher fan and new correct sleeve type thermostat. There is a new heater unit which has been tested and flows well . It seems ok unless its being booted , which is taking the pleasure ! Engine is Austin Healey 100 4cylinder 2.7l
Rarely would I ever consider such a thing an upgrade.

First, use a pressure gauge in the system to monitor pressure.

It might also do no harm to get some of those temperature stickers to see if you are in fact destroying your engine by cooking it, in lieu of some better temperature monitoring.

If you need better cooling, a better radiator, ensuring good cold airflow through the radiator at all times would be the first ports of call. Not a retrotfit electric water pump.

Although it may just be the case the core plugs or hoses were not installed correctly ?

You don't give any info about how hot it runs, whether you have any useful temperature monitoring at all etc etc ?

stevieturbo

17,746 posts

261 months

Saturday 8th February
quotequote all
gramos said:
Cap is .7 bar/ 10 psi , spec says 7 psi
And have you tested that it operates as expected ?

mwstewart

8,300 posts

202 months

Saturday 8th February
quotequote all
gramos said:
Looks like stem seals have gone one cyl #2, but that'll be unrelated to the cooling system issue.

Did this problem start when you fitted the electric water pump? Do you have a water temp gauge?

New rad, pump, etc. are all variables that need isolating and analysing.

gramos

Original Poster:

31 posts

127 months

Saturday 8th February
quotequote all
You missed the aluminium rad and know how to put an engine together , I did not call it an '" upgrade" , the car runs in a hot climate so these improvements were made to combat higher that UK temperatures .I will do a system pressure test next thank you.

gramos

Original Poster:

31 posts

127 months

Saturday 8th February
quotequote all
Yes , stat test opened at 72 C

gramos

Original Poster:

31 posts

127 months

Saturday 8th February
quotequote all
Not tested pressure cap but have several different pressure caps but produce no difference to the problem . Since fitting the DC pump there has been a tendency to blow hoses , maybe 4 times in 2+ years but very little actual mileage

gramos

Original Poster:

31 posts

127 months

Saturday 8th February
quotequote all
Ran up to temperature when stat opened at 120F and judging by the bubbles coming up in the rad looks like the head gasket is leaking into the cooling system as some have suggested.🙄 I don't have a ex gas analyser so .

GreenV8S

30,800 posts

298 months

Saturday 8th February
quotequote all
gramos said:
I replaced my water pump with a Davies Craig electric pump to help cooling
If you want to improve cooling I would have thought you would want to increase coolant flow, not massively reduce it. Have you looked at the size of the scroll inside those little pumps? They are weedy little things which will produce far less flow than the OEM mechanically driven pumps.

I'm afraid it's likely you've suffered local overheating and either blown a gasket or cracked a casting so the cooling system is being pressurised with combustion gasses. A block test aka sniff test may confirm this. Also check the pressure cap is working correctly - it should allow excess pressure to blow off rather than bursting hoses.

Richard-D

1,459 posts

78 months

Saturday 8th February
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i thought those electric coolant pumps were for keeping some flow after shutting the engine down, not as a main pump. Is that not the case?

TwinKam

3,321 posts

109 months

Saturday 8th February
quotequote all
gramos said:
Ran up to temperature when stat opened at 120F and judging by the bubbles coming up in the rad looks like the head gasket is leaking into the cooling system as some have suggested.?? I don't have a ex gas analyser so .
And you don't need one to test those bubbles, less than £20 (or €) will buy you one of these simple kits...



Chicken or egg? ...whatever the initial cause, a damaged head gasket (or worse) is often the outcome of overheating, as others have stated.

stevieturbo

17,746 posts

261 months

Saturday 8th February
quotequote all
gramos said:
Although I would also query, what looks like a BP5ES, yet a chunk is missing from the electrode on them all.

Unrelated to your problem I'm sure....but why ?