Clues please...

Joe Harding · Nov 15th, 2010, 08:50

Our 340 1.4 1988 overheats. Caught it before it went incandescent, but the fault seems to replicate itself, to wit:

From cold, engine temp rises, then at 3/4 way along gauge, series of plumbing bangs and belches, accompanied by coolant bursting out of the header tank.

Coolant then subsides down, losing about a litre in the process.

Top it up, and it is fine.

Action taken so far:

radiator - very tatty and possibly holed, so changed.

Thermostat, changed. (But which way round should it be mounted? Wax end towards or away from the engine.)

Pipework inspected, bleeder pipe found to be blocked. Unblock, and find we are at the following situation:

Once settled down, engine runs fine. Odd fluctuations in temp, but nothing alarming.
From cold, seems to be subject to the pressure problem, then losing coolant through the header tank.

Weird thing is, the themostatic valve fails to open initially. Once open, it all calms down.

Okay, I've pondered the head gasket, but why should it run for miles if that was faulty?

Help please.

mchudd · Nov 15th, 2010, 13:07

Hi mate.
You have probably just got an air lock.
Bleed the system and that should do it.
Cheers Mark.

Clan · Nov 15th, 2010, 13:43

You probably have the thermostat upside down the wax end should be down towards the engine so it can sense the circulating coolant in the head ..
You dont get air locks in volvo engines , one road test, the level drops , top up , job done ...

Joe Harding · Nov 15th, 2010, 15:46

I'm glad you think so too. Weird thing is, the Heinz manual shows it wrong. It shows the spring end towards the engine. And as far as I can recall, the car came with it fitted that way and has behaved normally for years.#

Anyone else fancy whipping the top hose off the pump and checking...?

Clan · Nov 15th, 2010, 16:22

the capsule bit should be at the bottom , the wide part which fits in the hose has a ridge on to locate it in the hose , this ridge should be at the bottom .

Joe Harding · Nov 16th, 2010, 08:25

Quote:

Originally Posted by Clan

the capsule bit should be at the bottom , the wide part which fits in the hose has a ridge on to locate it in the hose , this ridge should be at the bottom .

By 'eck lad, you're right! Stuck thermostat t'other way round and hey, temperature is dead level.
Thanks for that.

Cheers

granitegob · Nov 28th, 2010, 19:10

Quote:

Originally Posted by mchudd

Hi mate.
You have probably just got an air lock.
Bleed the system and that should do it.
Cheers Mark.

Seconded

Nov 15th, 2010, 08:50	#1
Joe Harding Premier Member Last Online: Yesterday 21:07 Join Date: Oct 2010 Location: Bristol	Clues please... Our 340 1.4 1988 overheats. Caught it before it went incandescent, but the fault seems to replicate itself, to wit: From cold, engine temp rises, then at 3/4 way along gauge, series of plumbing bangs and belches, accompanied by coolant bursting out of the header tank. Coolant then subsides down, losing about a litre in the process. Top it up, and it is fine. Action taken so far: radiator - very tatty and possibly holed, so changed. Thermostat, changed. (But which way round should it be mounted? Wax end towards or away from the engine.) Pipework inspected, bleeder pipe found to be blocked. Unblock, and find we are at the following situation: Once settled down, engine runs fine. Odd fluctuations in temp, but nothing alarming. From cold, seems to be subject to the pressure problem, then losing coolant through the header tank. Weird thing is, the themostatic valve fails to open initially. Once open, it all calms down. Okay, I've pondered the head gasket, but why should it run for miles if that was faulty? Help please.

Nov 15th, 2010, 13:07	#2
mchudd Senior Member Last Online: Jul 22nd, 2021 14:56 Join Date: Apr 2006 Location: BELFAST	340 Hi mate. You have probably just got an air lock. Bleed the system and that should do it. Cheers Mark.

Nov 15th, 2010, 13:43	#3
Clan Experienced Member Last Online: Today 00:12 Join Date: Jun 2007 Location: L/H side	You probably have the thermostat upside down the wax end should be down towards the engine so it can sense the circulating coolant in the head .. You dont get air locks in volvo engines , one road test, the level drops , top up , job done ... __________________ My comments are only based on my opinions and vast experience .

Nov 15th, 2010, 15:46	#4
Joe Harding Premier Member Last Online: Yesterday 21:07 Join Date: Oct 2010 Location: Bristol	Et tu, Clan I'm glad you think so too. Weird thing is, the Heinz manual shows it wrong. It shows the spring end towards the engine. And as far as I can recall, the car came with it fitted that way and has behaved normally for years.# Anyone else fancy whipping the top hose off the pump and checking...?

Nov 15th, 2010, 16:22	#5
Clan Experienced Member Last Online: Today 00:12 Join Date: Jun 2007 Location: L/H side	the capsule bit should be at the bottom , the wide part which fits in the hose has a ridge on to locate it in the hose , this ridge should be at the bottom . __________________ My comments are only based on my opinions and vast experience .

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