A cracked head or not a cracked head

[tarnowski1]

Hi all, long time lurker,

Throwing this out for ideas/thoughts

2002 D22 Navara King Cab,

Garage (Nissan main dealer) diagnosis: Cracked head or blown Head gasket, Wants £1000 (take engine apart) to confirm which it is, further £800 to fix head gasket or a further £2000 to fix cracked head

The symptoms that lead to this diagnosis:

Heating system only pumps out hot air after at least 15 minutes of running and only if above 2000 RPM. Drop below that immediately reverts to blowing cold air. Garage found radiator low on coolant which they topped up.

Heating has been acting up like this for 2 months prior to going into the garage for an oil filter change, I just asked them to have a shufti at it.

initial turn over in morning can be a little rough and take a couple of attempts, needs heater switch to fire but this is not different to last winter at minus or near zero temperatures. (battery is 6 months old). On initial fire she smokes white for initial exhaust blow, a second to two at most then clear.

thats it basically, Engine's done 120K miles, she might be slightly gutless at 70MPH+ but if she is its not a new thing.

No computer errors.

Since garage topped up coolant I've run her for two days, no drop in level and still no heating. Oil is uncontaminated, usual colour and viscosity. No obviously leaks of coolant.

Edit- note the aircon is dead in the car, has been since I bought her, blown bearings so its disconnected from system (as in fan belt removed)

Regards
Matt

 

[Rumpig]

Sounds more like stuffed glow plugs but the heater only blowing hot air above 2000rpm is odd, may be a blocked heater core or maybe air trapped in the cooling system.

 

[Hatchy]

I'd say air in the system. The heater hoses are fairly high on these.

 

[tweak'e]

first thing is......what engine do you have?

 

[tweak'e]

it could simply be blocked up heater core.
also failing water pump
or thermostat is stuck open or has been removed.

 

[Kawaiman]

Does it have a thermostat in it?

 

[Old.Tony]

Given its age, and that the cooling system was low on coolant, I'd think air too, or highly restricted passageways in or to the heater matrix. You can check for blockages yourself - this is what I used to do before the days of coolant-only (and yours might be fine like this too):

In the firewall there will be two pipes that have hoses connecting to the cooling system. Clamp both hoses, undo them and remove. Put the same sized hose on both, long enough for one to reach near the ground and one so you can connect a garden hose nozzle into it. Turn on the tap - you shouldn't experience a large mount of pressure building up in the hose, and the water should flow fairly well out the other hose.

To get rid of air pockets you'd usually give the thing a rev, the air would get sucked along into the radiator and job done.

Here's the major dilemma you face: you might indeed have a cracked head or a blown gasket. If you don't though, you're throwing a lot of cash at the car for zero gain and the worst part is, they could disassemble your car, find nothing, put a new gasket in and say they found a blown gasket, charging you for the effort. Unfortunately that won't have fixed the problem and you're sitting there looking at the receipts for wasted cash.

Checking other things first before a big outlay is always going to take some time, particularly if you're getting ideas from a forum and more particularly if you're asleep when we're answering on the other side of the world. If that time is too much, then get Nissan to do it - but I'd make sure that you get them to confirm (in writing) that they are doing this work to fix the symptoms you're experiencing, and not to simply do the job of replacing a head gasket or checking the head. That way, they are obligated to fix the car even if it wasn't a head gasket/cracked head!

 

[tarnowski1]

Hi all,
sorry for the delay in replying, unexpected arrival of puppies lost me the weekend

Engine is 2.5 TDI, exactly which model might take some digging as its a replacement engine for the original which suffered from the rod throwing issue common in the 2002 D22.

Well I've put 500 miles on her in the last 5 days and the coolant level hasnt dropped, heating is still borked but other than that not noticing an issue!

IIRC the thermostat is a sod to get to but will have a look at that and the suggestion of air in the system this weekend. Assuming it doesnt roll over dead before then

cheers for the ideas on what to look for.

Regards
Matt

 

[andywerder]

mine just lost power, going up a hill on the highway, lost accelaration then died and started smoking under the bonnet.
Thought it was timing chain, mechanic where it was towed to saying blown head, need new engine because its not worth fixing due to 300 000 km on engine.