4.2 series 1 e-type throwing coolant

[Jim_Newman]

So, I pull into my garage after a nice run and the header tank overflow pipe is expelling coolant at an alarming rate. The engine had not shown signs of overheating and the fan had not come on. The bonnet did seem really hot to the touch though. Suspected problem - blown head gasket. Pulled head, found it to be slightly warped (0.005in), had it milled, replaced gaskets and all cooling system hoses, put it all back together and took it for a drive. When I pulled into my garage, coolant again started exiting from the overflow. Again engine did not appear to overheat when driving. Could this be a sign of a cracked block? Tell me it isn't so and that some simple problem is the culprit.
Thanks for the help.
Jim

 

[toysrrus]

Hi Jim,

I`m typ. on the Spridget & Triumph forums. I`ve owned 4 E-Types (Series I & II). I`ve never had that problem but overheating was always a problem especially in stop & go traffic.

What I would check first (Cheap Check) is the "Overflow Cap". I used to drive around with the cap loosely fitted so It can vent. Whats the PSI reading on your cap? What you may also want to check is to see if the Hoses are collapsing or not. Of course the other thing; "Thermostat" but you say the engine is "NOT" overheating? Find yourself one of those "Digital Heat Guns" (Most Service Stations etc have one) & check the temps at all points (Engine, Radiator, Thermostat, Overflow, Exhaust etc). That should tell you if your "Guage" is reading correctly! With the Bonnet hot to the touch; You just may be "Overheating"!

"Cracked Block"? These loveyl engines are virtually "Bullet Proof" so that is most likely "NOT" the problem (I would hope so anyway)!

My $.02 worth. I`m sure there are some folks here who could dwell on that further.

Best Wishes,

Russ

 

[mikespain]

Try changing the cap first,it might be blowing off at a low pressure as it is not showing overheatng,the early 3.8 used a 4lb cap later used 7lb cap series 1 4.2 uses 7 lb cap later S2 non AC uses 7lb and with AC and the S3 use a 13lb cap.The temp always rises slightly when you first stop as there is no water flow or air flow to cool the engine so the water expands some and creates slightly more pressure.As Russ says unlikely to be a cracked block

 

[Basil]

I would concur with checking the cap first. Back in the day before I took my Series I apart for restoration, I had a similar problem due to a bad cap.

 

[Jim_Newman]

Thanks all for the advice. I'll let you know if it works.
Just a follow up question - Is there a valve somewhere on the head that permits one to bleed air from the cooling system?
Thanks again
Jim

 

[Jim_Newman]

Installed new 7lb. cap and went for quick drive. Came home, coolant stayed put. No puking this time. But it was a cold day. I won't know for sure till the hot weather driving comes back - but I'm hopeful.
Thanks for the advice.
Jim

 

[Basil]

Thanks all for the advice. I'll let you know if it works.
Just a follow up question - Is there a valve somewhere on the head that permits one to bleed air from the cooling system?
Thanks again
Jim

No, I don't think so. There is a spigot on the block but that's for draining the block. Any air should naturally aspirate out as the fluid is circulated. If not, then you may be sucking in air, which could point to a bad head gasket.