Coolant leak .... between firewall and engine ???

[vq35]

Hi
2 days ago developed a steady heavy leak - access = NOT POSSIBLE - WTF ??? Is this common?
any knowledge of cost/experience/solutions/pics etc would be appreciated.

[Towncivilian]

Check the heater hoses. Sorry for the not-so-great picture:

[vq35]

Hi Town
So far took it to the nearest shop - showed them the leak and they removed plenum (upper/lower) and I asked them to replace the spark plugs/pcv and gaskets while they were at it (apparently they did this with all aftermarket gaskets - didnt manage to change the pcv valve which = big missed opportunity, and replaced the plugs with ngk iridium)

so now no more coolant leak BUT the car is hesitating and there is a significant delay between gas and actual take off - we checked and there are p0325 p1145 AND p1491 codes triggered - what the fffff, is this normal, any solutions or guidance would be appreciated - I would love to DIY this and 10 being a prof., I am a 5 in terms of feeling comfortable doing this ....
again any guidance much appreciated - I am tempted to suspect that they 'created' a new problem but I will refrain from that as I do not know so cannot pass judgement....and yes I am planning on taking it back to try and resolve this but would like the option of just forgetting about it, be thankful that the hard to reach coolant leak was resolved, and that I paid 50% of what nissan quoted me .

thanks

[Towncivilian]

You should have had the shop apply red threadlocker to the power valve screws while the lower intake manifold was off the vehicle. Shame they missed the PCV valve too since it's a real pain to access.

What was causing the leak? One of the manifold gaskets?

P1145 is the driver's side camshaft position sensor. Swap it with the passenger side to see if the code changes to P1140; if it does, replace the sensor. This guide has information about the sensors' locations.

P1491 is likely unrelated; the code is "VACUUM CUT VALVE BYPASS VALVE". See EC-583 for a diagnostic procedure.

P0325 is probably a cause of one of the other codes and should go away once the codes are resolved and performance improves.

[vq35]

mine is the manual transmission = no power valves

the shop said they would clean it and put it back in - should I redo the gaskets and put in the pcv valve??
the leak was unrealted to the manifold gaskets ...... I am driving the truck now, it idles fine and is fine on part throttle but anything above that = there is a delay in power delivery and when it comes it is less than usual - I was thinking some sort of vacuum leak or something or is there a reset that I should normally do ??
thanks

[Towncivilian]

I assume the shop would have replaced the PCV valve if it were defective. If you paid for PCV valve replacement specifically and it was not done, I'd complain about that.

I don't believe you should need to perform any relearn procedures - at least I didn't have to when I replaced my PCV valve and all that other stuff involved.

Poor performance is likely related to the P1145 code.

[vq35]

thank you for this - Town - however my performance is more like a hesitation and unwillingness to rev right away - I have decided to just take everything apart and see if this works (whie I put in the pcv)
would the knock sensor produce a similar reaction (I read somewhere that a faulty one would cause the timing to retard - which is what it feels like....)
I didnt clean the throttle or maf sensor so I will do this also and see what happens
thanks again for the help Town

[Towncivilian]

Have you replaced the fuel filter? A restricted fuel filter can cause such hesitation. I'd thoroughly clean the throttle body while you have it disconnected from the intake manifold during PCV valve replacement. Be sure to also purchase the grommet that goes around the PCV valve itself. If you need part numbers for those as well as the manifold/TB gaskets, see this post. I would also suggest adding a PCV catch can while everything is apart - see this post. A PCV catch can will condense oil vapors that are expelled from the PCV valve and keep the throttle body cleaner, as well as eliminate oil mist collecting in the intake manifold.

You can measure the resistance of the knock sensor to see if it is faulty. See EC-334 of the FSM.

[vq35]

Town, I dont understand how your brethren on Nico are not as helpful and generally cool as yourself......it seems they are a little burnt out (understandable) but you are very good at this.....please keep it up, well deserved acknowledgement ....good stuff

[vq35]

so far have changed the fuel filter - no change in hesitation - next will tackle 1491 and see where this leads as now I am thinking its either that or an actual leak from the new aftermarket intake/exhaust gaskets (btw lotsa pressure in fuel lines so fuel pump ok) hate this s***, only rarely let me down though and usually costly ....let me know if you can think of anything else

thanks