Cooling system design

Newbie Joined: 04 Dec 2004 Posts: 17

On my Laguna II I've noticed that the coolant in the reservoir (expansion tank) stays cold. Even when the car has been running and the engine, rad, hoses, heater etc. are all nice and hot

Whereas with the 19, the coolant in the reservoir gets hot when the engine gets hot.

Different cooling system designs obviously but can anyone explain the difference.

Also, the Laguna heats up a lot quicker than the 19 after a cold start, I assume this is due to the difference in design.

Forum Moderator Joined: 02 Mar 2004 Posts: 19978

how many pipes does your laguna tank have? What engine?

They are different engine to engine, some the tank is remote and only comes into play when the stat opens, otheres liek the 19 its part of the system and is used all the time.

It heats up quicker if the coolant only circulates through the engine and heater instead of engine heater, remote resovoir.

Newbie Joined: 04 Dec 2004 Posts: 17

Chris it's the 1.6 engine in the Laguna and the Energy in the 19. Not sure how many pipes there are going to the Laguna's tank. There is one pipe near the top of the tank. I have never seen any coolant coming out of this pipe. Generally there doesn't seem to be a lot happening in the Lag's tank. The coolant seems to remain stagnant and cold even when the rad is hot. And it doesn't seem to build up much pressure either, open the cap on a hot engine and very little pressure is released.

Forum Moderator Joined: 02 Mar 2004 Posts: 19978

on the 1.6 lag it should flow through that pipe. Its more than likely blocked which is common. Pop it off (use mole grips on the spring clips) and use a screwdriver to poke through the crud then wash it through.

Newbie Joined: 04 Dec 2004 Posts: 17

Will do Chris, but first I'm going to observe the tank a bit more as I may have been mistaken about no coolant coming out of the pipe. It is hard to imagine that the pipe would be blocked as car is only 2 years old?

One reason for asking these questions about the system is I'm thinking of a coolant change and flush as it is starting to go a bit orange.

Forum Moderator Joined: 02 Mar 2004 Posts: 19978

coolant should be changed every year without fail if you want the cooling system to stay at peak performace. It doesn;t tyake much to block it tbh.

Rev the engine and hold the revs up and watch the pipe.

The system should be building up pressure btw, is it leaking at all?

Level 10 User Joined: 05 Mar 2005 Posts: 570

Better have mind done asap then Embarassed

New head to go on anyway! Very Happy